Controlling incremental technical debt

Last updated on January 20th, 2019 at 01:54 pm

All technical debt in enterprise assets is either incremental technical debt or legacy technical debt.  Incremental technical debt is technical debt newly incurred. It can be newly incurred exogenous technical debt, or it can be endogenous technical debt incurred either in projects currently underway, or projects just recently completed. Legacy technical debt is technical debt associated with assets, and which wasn’t incurred recently or which exists in any form prior to undertaking work on those assets. All legacy technical debt was at some point incremental technical debt. The vast amounts of legacy technical debt most organizations now carry are nothing more than the accumulation of incremental technical debt. The path to managing legacy technical debt therefore begins with controlling incremental technical debt.

A sinking rowboat
A sinking rowboat provides a useful metaphor for illustrating the effects of incremental technical debt. The enterprise is the rowboat; the leaks are the properties of the enterprise and its environment that lead to creating incremental technical debt; water entering the boat through leaks is incremental technical debt; the accumulated water in the bottom of the boat is legacy technical debt.

Organizations are more likely to gain control of their legacy technical debt portfolio if they begin by controlling the formation of incremental technical debt, and its transformation into legacy technical debt. A metaphor might make this clear:

If you find yourself in a sinking rowboat, bailing out at least some of the water is a good idea, and it might be necessary in the short term. But at some point, fixing the leaks where the water comes in is advisable. Unless you address the leaks that already exist, and prevent new ones from forming as the rowboat ages, your fate is sealed. You’ll spend increasing portions of your time, energy, and resources bailing out your leaky rowboat, and declining portions of your time, energy, and resources rowing the boat towards your objective. And when you do devote some time and energy to rowing towards your objective, you’ll find the rowing surprisingly difficult, because the boat is lower in the water, and because you must propel not only the mass of the boat and its payload, but also the dead weight of the water in the bottom of the boat.

In this metaphor, legacy technical debt is the water in the bottom of the boat, and incremental technical debt is the water coming in through the leaks. The leaks are the proximate “causes” of technical debt. The root causes of the leaks are the root causes of technical debt.

If the enterprise is in the midst of a legacy technical debt emergency, retiring some of it is necessary in the short term. But unless the enterprise addresses incremental technical debt and its root causes, a new burden of legacy technical debt will accumulate. That accumulation is then likely to eliminate the benefits of having retired the current burden of legacy technical debt.

So after the legacy technical debt emergency is passed—or if resources permit, during the emergency—establishing measures, procedures, and practices for controlling incremental technical debt would be prudent.

This change might be less challenging than it sounds. With respect to endogenous incremental technical debt, the teams that incurred it are either still at work, or just recently dispersed. Their understanding of the incremental technical debt is still fresh in their minds. If their projects are still underway, and if budget and schedule permit, retiring the incremental technical debt in the context of those projects is a superior strategy. For projects that have already delivered their work products, a somewhat less preferable—but still practical—approach involves re-assembling some of the team to retire the incremental technical debt as soon as possible, while memories are still fresh. Other approaches might be needed for incremental exogenous technical debt.

For the most part, the problem of controlling incremental technical debt isn’t a technical one. It usually reduces to a problem of finding time and resources to undertake the task.

Why resources aren’t available to retire incremental technical debt

The immediate reason why most teams don’t have enough resources to retire their incremental technical debt is that the organization, as a whole, doesn’t plan for retiring incremental technical debt incrementally. This immediate reason, though, isn’t fundamental. The lack of resources is a symptom of deeper dysfunctions in the organization. The real question is this: Why do so many organizations fail to allocate time and resources to retire incremental technical debt incrementally? Here are three reasons.

Misunderstanding (or no understanding) of the concept of technical debt

The organization is unlikely to be able to manage any kind of technical debt unless its people understand the concept. They must understand that technical debt isn’t necessarily the result of engineering malpractice. Much technical debt arises either as a natural result of working with technology, or as a result of organizational forms that compel people to behave in ways that lead to generating technical debt. Unless the people of the organization accept these truths, allocating sufficient resources to managing incremental technical debt is unlikely.

Not appreciating the MICs

Decisions regarding technical debt management ultimately reduce to a choice between allocating precious resources to technical debt retirement, and allocating them elsewhere. To make this choice responsibly, it’s necessary to fully appreciate the cost of carrying technical debt. Most believe that these costs appear in the form of lost engineering productivity. While that is indeed a factor, other factors can be far more important.

For example, if entry into an important market is delayed by even as little as 30 days due to debt-depressed engineering productivity, the financial consequences can be enormous and insurmountable. Or delays in diagnosing and repairing a fault in a product can produce financial liabilities that can actually sink the company. When one considers all possible financial consequences of carrying technical debt, it becomes clear that managing technical debt effectively is actually a strategy for survival. The decision to allocate appropriate resources to incremental technical debt retirement does require modeling these costs—calculations that few organizations actually undertake.

Miscalculating projections of returns on investments

Failing to estimate MICs with sufficient precision is problematic, as noted, because it reduces the quality of decisions regarding short-term resource allocations. But it also affects long-term projections, which depend on estimating returns on investments. For example, to choose between investing in retiring incremental technical debt from an asset and investing in new capabilities for the same asset, one must compare the projected value of each choice. If the decision-maker’s understanding of the technical debt concept is deficient, or if the calculations of MICs now or in the future are incomplete or underestimated, the investment decision is likely to be biased in favor investing in new capabilities. Incremental technical debt retirement is thereby systematically deferred or avoided altogether.

Policy recommendations for controlling incremental technical debt

The simplistic approach to controlling incremental technical debt is to provide more money to projects and to engineering functions. While that approach will be somewhat helpful, its results will likely be disappointing when compared to approaches that combine resource augmentation with changes in enterprise policy, processes, and culture.

Let’s begin with an example of a needed cultural change. Nearly anyone who makes or influences decisions might occasionally bear some responsibility for incurring incremental technical debt. To achieve effective control of technical debt requires that all such people understand how to change their behavior, whether they’re acting individually or in collaboration with others. Any guiding principle offered to them must be simple to state and easy to understand, because we must communicate it to nearly everyone in the enterprise. Here’s a sample statement of a useful such principle:

Those whose decisions cause the enterprise to incur technical debt are accountable for securing the resources needed to retire that debt, and for supplying compensating resources to those within the enterprise, or among its customers, who suffer depressed operational effectiveness during the period in which that technical debt is outstanding.

I call this the Principle of Accountability. It’s a corollary of what Weinberg calls “Ford’s Fundamental Feedback Formula” [Weinberg 1985], which captures the idea that people make better choices when they must live with the consequences of those choices.

General guiding principles are necessary, but not sufficient. Here are five examples of changes that help in controlling incremental technical debt [Brenner 2017b].

1.       Adopt a shared concept vocabulary

There must be general agreement among all parties about the meanings of concepts that relate to incremental technical debt formation.

Examples: the definitions of “done” vis-à-vis projects, strategic technical debt, reckless technical debt, unethical technical debt, exogenous-technical-debt, endogenous technical debt, MICs, MPrin, and more. An enterprise-wide education program, including on-line reference material and new-employee orientation components, are probably also necessary.

2.       Accept that technical debt is a fact of technological life

There is a widespread belief that most technical debt results from engineering malpractice. Although some technical debt does arise this way, most does not. For examples of other causes, see “Non-technical precursors of non-strategic technical debt.” Some technical debt arises because of advances external to the enterprise, beyond its control. Development-induced or field-revealed discoveries are especially difficult to avoid. In many instances, technical debt is an inevitable result of using technology.

3.       Track the cost of carrying technical debt

The cost of retiring a particular class of technical debt (its MPrin) is significant only in the context of planning or setting priorities for resource allocation. In all other contexts, knowing that cost has little management value. What does matter, at all times, is the cost of carrying that technical debt—the MICs, or metaphorical interest charges. (See “The Principal Principle: Focus on MICs.”) MICs can fluctuate wildly [Garnett 2013].

Build and maintain expertise for estimating and tracking the costs of incurring and carrying each class of technical debt. Know how much each kind of technical debt contributes to these costs, now and for the next few years.

4.       Assign accountability for kinds of technical debt

Some kinds of incremental technical debt result from actions (or inactions) within the enterprise; some do not. To control the kinds of incremental technical debt that arise from internal causes, hold people accountable for the debt their actions generate. Use Fowler’s Technical Debt Quadrant [Fowler 2009] as the basis for assessing and distributing internal financial accountability for debt retirement costs (MPrin) and metaphorical interest charges (MICs). For example, in Fowler’s terms, a Reckless/Inadvertent incident could carry a rating that would lead to imposing higher assessed charges for the debt originators than would a Prudent/Deliberate incident, the charges for which might be zero.

5.       Require that deliberately incurred technical debt be secured

In the financial realm, secured debt is debt for which repayment is guaranteed by specifically pledged assets. By analogy, secured technical debt is technical debt for which resources have been allocated (possibly in a forward time period) to guarantee the debt’s retirement and possibly its associated MICs.

This policy implies that deliberately incurred technical debt, whether incurred strategically or recklessly, must be secured. If anyone involved in a development or maintenance effort feels that technical debt has been incurred, a dispassionate third party, unaligned with any function involved in the effort, reviews project deliverables for the presence of technical debt. However, allocating future resources might require securing commitments of resources for fiscal periods beyond the current one. For many organizations, such forward commitments might require modifying the management accounting system.

Last words

Controlling incremental technical debt requires changes well beyond the behavior and attitudes of engineering staff, or the technologies they employ. Achieving control of incremental technical debt formation requires engagement with enterprise culture to alter the behavior and attitudes of most of the people of enterprise.

References

[Brenner 2017b] Richard Brenner. “Managing Technical Debt: Nine Policy Recommendations,” Cutter Consortium Executive Update 18:4, 2017.

Available: here; Retrieved: December 29, 2017

Cited in:

[Fowler 2009] Martin Fowler. “Technical Debt Quadrant.” Martin Fowler (blog), October 14, 2009.

Available here; Retrieved January 10, 2016.

Cited in:

[Garnett 2013] Steve Garnett, “Technical Debt: Strategies & Tactics for Avoiding & Removing it,” RippleRock Blog, March 5, 2013.

Available: here; Retrieved February 12, 2017.

Cited in:

[Weinberg 1985] Gerald M. Weinberg. The Secrets of Consulting. New York: Dorset House, 1985.

Ford’s Fundamental Feedback Formula. Order from Amazon

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Retiring localizable technical debt

Last updated on May 21st, 2019 at 07:43 am

When technical debt appears as discrete chunks—that is, when it’s localizable—we can often retire the debt incrementally, system-by-system, module-by-module, or even instance-by-instance. These approaches offer great flexibility, both technically and financially, which makes retiring localizable technical debt a particularly manageable challenge.

Localizable technical debt

Electricity pylons, Hamilton Beach, Ontario, Canada
Electricity pylons, Hamilton Beach, Ontario, Canada: a small part of the AC power grid, which seems destined one day to manifest a great deal of non-localizable technical debt. Photo by Ibagli courtesy Wikimedia Commons
Pylons in the same line are visible in Google Street View.

In “Technical debt in a rail system,” I explored the case of Amtrak’s Acela Express. In that example, I explained that Acela’s passenger cars are designed to tilt to compensate for centrifugal forces that appear when the train rounds curves. The technical debt is in the form of tracks that were too close together to permit the trains to tilt as much as they’re designed to, which limits the trains’ speed rounding curves. The instances of this debt are the curves in which the tracks are too close together. These instances are thus inherently localizable.

In “How technical debt can create more technical debt,” I described an example in which an organization is unable to upgrade its desktop computers from Windows 8 to Windows 10. In this case, each computer running Windows 8 is an instance of this form of technical debt.

Both of these examples illustrate the sorts of technical debt in which the instances are localizable—each instance is self-contained, and we can “point” to it as an instance of the debt in question. But localizable technical debt need not be associated with hardware. In software systems, for example, localizable technical debt can exist in a module interface, which might have been designed to meet a requirement that’s no longer relevant. That module and any other modules that interact with that interface manifest that technical debt.

Non-localizable technical debt

Non-localizable technical debt is debt for which the instances are amorphous or system-wide, or span the bulk of the system, if not all of it. Retiring non-localizable technical debt typically requires extensive re-engineering of the assets that manifest it.

For the most part, non-localizable technical debt arises at the level of system architecture or above. One can easily imagine this occurring in software systems, where physical constraints have little meaning, but let’s consider a hardware system to illustrate the importance of this concept.

Until relatively recently in the United States, most electric power consumers used power for incandescent lamps, heating, or for electric motors in elevators, refrigeration, home appliances, pumps, and so on. These applications are compatible with an alternating current power distribution system (AC grid). The AC grid is more efficient than an equivalent direct-current architecture (DC grid) when power generation plants are few and relatively distant from power load sites, because transmission losses are lower for AC than for DC.

However, advances in electronics and in distributed power generation technologies are eroding the advantages of the AC grid [Dragičević 2016]. Most electronic devices, including phones, computers, rechargeable power tools, LED lighting, and electric vehicles use DC internally. To access the AC grid, they use converters that change AC power into DC power, which entails efficiency losses due to the conversion. Moreover, solar power generation systems such as photovoltaics generate DC inherently. Modern wind turbines generate AC at a frequency determined by wind power conversion efficiency, but they then convert it to DC before a second conversion to AC at the frequency the grid requires. And because solar and wind power generators are geographically dispersed, they’re often situated near their load sites, as for example, a photovoltaic array on the roof of a home would be. Therefore, the losses involved in transmission from generation site to load site are much less important than they would be if the generation sites were few, concentrated, and at great distances from the loads they serve.

Our current AC grid architecture is likely to become a net disadvantage in the not-too-distant future. If that does happen, we could come to regard the current AC grid, and the devices that are designed for it, as manifesting technical debt. However, localizing that debt in each device and each component of the AC grid would make little sense. The technical debt in question would reside in the grid architecture, as a whole. It would be inherently non-localizable.

Addressing localizable technical debt

As noted above, we can often retire localizable technical debt incrementally—instance-by-instance. In many cases, this enables engineers to address the debt at times and in sequences that are compatible with organizational priorities and within the organization’s resource capacity in any given fiscal period. Although this isn’t always possible for localizable technical debt, and although engineers are often justifiably averse to the temporary non-uniformity that results from incremental debt retirement, exploiting localizability when planning debt retirement is often a useful strategy for retiring technical debt economically.

Incremental retirement of localizable technical debt does present some problems. During the retirement process, for any given instance, it might be necessary to install temporary structures to enable continued operation with minimal service disruption. For example, with the Acela tracks, an alternate line might be needed while the new track is installed, or the new track might need to be installed at some distance from the existing track while trains continue using the existing track. Either approach requires investment beyond the investment required for the new track itself. Some managers have little appetite for such temporary investments. But temporary investments are in a real sense part of the MICs on that debt. They’re unusual, as MICs go, in the sense that they’re incurred as part of the debt retirement effort, but they’re still MICs. In a way, they’re analogous to the charges that might appear when terminating an auto lease.

Another consideration when addressing localizable technical debt is its entanglement with other forms of technical debt. With respect to the effort to retire one kind of localizable technical debt, these other forms of technical debt are what I’ve called auxiliary technical debt (ATD). Consider carefully the time order of efforts to retire the localizable technical debt and one or more forms of its ATD. Because retiring localizable technical debt can seem deceptively straightforward, the temptation to deal with it before addressing some of the ATD can be difficult to resist. But dealing with some of the ATD first might actually be the wiser course when, for example, doing so eliminates numerous instances of the localizable technical debt.

One note of caution

Within the category of localizable technical debt are some kinds of debt that are so widespread in the asset that retiring them affects a large part of the asset, if not all of the asset. While it’s true that each instance of such debt is identifiable and localized, the instances are so widespread that they collectively have the properties of non-localizable debt as far as retirement efforts are concerned. Incremental retirement might still be possible, but a more global retirement effort might be safer and less disruptive. One approach, usually favored by the technologists, is to suspend all other work while the debt in question undergoes retirement. While that approach might indeed be safest, all stakeholders must accept and understand the technical issues, and the technologists must understand the concerns of all stakeholders. A joint decision about the retirement strategy among all stakeholders, including technologists, is recommended.

Last words

In the context of debt retirement projects, localizable technical debt provides needed flexibility. Often, the non-uniformity that results from retiring localizable technical debt instance-by-instance can be reduced before the debt retirement project is completed. In the meantime, the team can be relatively free to retire the localizable debt in whichever order is most fitting.

References

[Brenner 2017b] Richard Brenner. “Managing Technical Debt: Nine Policy Recommendations,” Cutter Consortium Executive Update 18:4, 2017.

Available: here; Retrieved: December 29, 2017

Cited in:

[Dragičević 2016] Tomislav Dragičević, Xiaonan Lu, Juan C. Vasquez, and Josep M. Guerrero. “DC Microgrids–Part II: A Review of Power Architectures, Applications and Standardization Issues,” IEEE Transactions on Power Electronics, vol 31:5, 3528-3549, 2016.

Cited in:

[Fowler 2009] Martin Fowler. “Technical Debt Quadrant.” Martin Fowler (blog), October 14, 2009.

Available here; Retrieved January 10, 2016.

Cited in:

[Garnett 2013] Steve Garnett, “Technical Debt: Strategies & Tactics for Avoiding & Removing it,” RippleRock Blog, March 5, 2013.

Available: here; Retrieved February 12, 2017.

Cited in:

[Weinberg 1985] Gerald M. Weinberg. The Secrets of Consulting. New York: Dorset House, 1985.

Ford’s Fundamental Feedback Formula. Order from Amazon

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Legacy technical debt retirement decisions

Last updated on January 5th, 2019 at 10:32 am

Decisions to retire the legacy technical debt carried by irreplaceable assets are not to be taken lightly. As decision makers gather information and recommendations from all around the organization, most will discover that information and recommendations aren’t sufficient for making sound decisions about technical debt retirement. The issues are complex. Education is also needed. It’s entirely possible that in some organizations, confronted with a set of decisions regarding legacy technical debt retirement in irreplaceable assets, the existing executive team might be out of its depth. To understand how this situation can arise, let’s explore the nature of legacy technical debt retirement decisions.

A common technical debt retirement scenario

What compels the leaders of a large enterprise to consider retiring the technical debt encumbering one of its irreplaceable assets is fairly simple: cost. Decision makers usually begin by investigating the cost of replacing the asset—the option I’ve oh-so-cleverly called “Replace the Asset.” They then typically conclude that replacement isn’t affordable. At this point, many decision makers choose the option I’ve called “Do nothing.” Time passes. A succession of incidents occurs, in which repairs to the asset or enhancements of the asset are required. And I use the term required here to mean “essential to the viability of the business.”

Two alternatives to retiring legacy technical debt in irreplaceable assets
Two alternatives to retiring legacy technical debt in irreplaceable assets. Neither one works very well.

Engineers then do their best to meet the need, but the cost is high, and the work takes too long. The engineers explain that the problems are due, in part, to the heavy burden technical debt in this particular asset. Eventually the engineers are asked to estimate the cost of “cleaning things up.” Decision makers receive the estimates and conclude that it’s “unaffordable right now.” They ask the engineers to “make do.” In other words, they stick with the Do Nothing option.

After a number of cycles repeating this pattern, decision makers finally agree to provide time and resources for technical debt retirement, but only because it’s the least bad alternative. The other alternatives—Replace the Asset, and Do Nothing—clearly won’t work and haven’t worked, respectively.

So there we are. The organization has been forced by events to address the technical debt problems in this irreplaceable asset. And that’s where the trouble begins.

Decisions about retiring legacy technical debt

In scenarios like the one above, the fundamental decision has already been made: the enterprise will be retiring legacy technical debt from an irreplaceable asset. But that’s just the first ripple of waves of decisions to come, made by many people in a variety of roles throughout the enterprise. Let’s now have a look at a short catalog of what’s in store for such an enterprise.

Recall that most large technical debt retirement projects probably exhibit a high degree of wickedness in the sense of Rittel and Webber [Rittel 1973]. One consequence of this property is the need to avoid do-overs. That is, once we make a decision about how to proceed to the next bit of the work, we want that decision to be correct, or at least, good enough. It should not leave the enterprise in a state that’s more difficult to resolve than the state in which we found it. Since another property of wicked problems is the prevalence of surprises, most decisions must be made in a collaborative context, which affords the greatest possibility of opening the decision process to diverse perspectives. We must therefore regard collaborative decision-making at every level as a highly valued competency.

What follows is the promised catalog of decision types.

Strategic decisions

This decision category leads the list because it provides the highest leverage potential for changing enterprise behavior vis-à-vis technical debt. Organizations that are confronting the problem of technical debt retirement from irreplaceable assets would do well to begin by acknowledging that although they might be able to devise tactics for dealing with the debt burdening these assets right now, they must make a strategic change if they want to avoid a recurrence. Accumulating debt to a level sufficient to compel chartering a major debt retirement project took time. It took years of deferring the inevitable. A significant change of enterprise strategy is necessary.

When changing complex social systems, applying the concept of leverage provides a critical advantage. In this instance, following the work of Meadows [Meadows 1997] [Meadows 1999] [Meadows 2008], we can devise interventions at several points that can have great impact on both the level of technical debt and its rate of accumulation. The leverage points of greatest interest are Feedback Loops, Information Flows, Rules, and Goals. For example, the enterprise can set a strategic goal of a specific volume of incremental technical debt incurred per project, normalized by project budget, as I discussed in the post, “Leverage points for technical debt management.”

One might reasonably ask why enterprise strategy must change; wouldn’t a change in technology strategy suffice? Changing how engineers go about their work would help—indeed in most cases it’s necessary. But because the conditions and processes that lead to technical debt formation and persistence transcend engineering activities, additional changes are required to achieve the objective of controlling technical debt.

Some technical debt is strategic—it’s incurred as the result of a conscious business decision. But some is non-strategic. We might even be unaware of how it occurred. However, both kinds of technical debt can arise as a result of non-technical factors. Read a review of non-technical precursors of non-strategic technical debt.

Organizational decisions

Before chartering a technical debt retirement project (DRP) for an irreplaceable asset, or a group of irreplaceable assets, it’s wise to consider how to embed that project in the enterprise.

The default organizational form for debt retirement projects concerned with an asset A is usually the same form that would be used for major projects focused on asset A. If the Information Technology (IT) unit would normally address issues in A, the debt retirement effort usually would be organized under IT. If A is a software product normally attended to in a product group, that same group would likely have responsibility for the DRP for asset A.

Although these default organizational structures are somewhat sensible, both technically and politically, there’s an alternative approach worth investigating. It entails establishing a technical debt retirement function that becomes a center of excellence for executing technical debt retirement projects, and for developing and injecting sound technical debt management practice into the enterprise. Such an approach is especially useful if multiple debt retirement projects are needed.

The fundamental concept that makes the center-of-excellence approach necessary is the wickedness of the technical debt retirement problem. To address the problem at scale requires capabilities beyond what IT can provide; beyond what product units can provide; indeed, beyond what any of the conventional organizational elements can provide. The reason for this is that the explosion of technical debt in most organizations is an emergent phenomenon. Every organizational unit contributed to the formation of the problem. And every organizational unit must contribute to its resolution.

A technical debt center of excellence is an approach that might be capable not only of synthesizing the expertise of all elements of the enterprise, but also might be capable of bringing new approaches into the enterprise from external sources.

Engineering decisions

Engineers have a tendency to identify and classify technical debt items on technical grounds. Further, they tend to set technical debt retirement priorities on a similar basis. That is, they’re inclined to set priorities highest for those debt items that they (a) recognize as debt items and (b) see as imposing high levels of MICs charged to engineering accounts. Engineers are less likely to assign high priorities to technical debt that generates MICs that are charged to revenue, or to other accounts, because those MICs are less evident—and in many cases invisible—to engineers.

Decisions regarding recognition of technical debt items and setting priorities for retiring them must take technological imperatives into account, but they must also account for MICs of all forms. Priorities must be consistent with enterprise imperatives.

Decisions about pace

Paraphrasing Albert Einstein, technical debt retirement projects should be executed as rapidly as possible, and no faster. The tendency among non-engineers and non-technical decision-makers is to push for rapid completion of debt retirement projects, for three reasons. First, everyone, like the engineers, wants the results that debt retirement will bring. Second, everyone, like the engineers, wants an end to the inevitable disruptions debt retirement projects cause. And finally, the longer the project is underway, the more it might cost.

For these reasons, once the decision to retire the debt is firmly in hand, the enterprise might have a tendency to apply financial resources at a rate that exceeds the ability of the project team to execute the project responsibly. When that happens, rework results. And for wicked problems like debt retirement, rework is the path to catastrophe.

Decisions about pace and team scale need to be regarded as tentative. Regular reviews can ensure that the resource level is neither too low nor too high. Even when the engineers are given control over these decisions, they must be reviewed, because pressures for rapid completion can be so severe that they can compromise the judgment of engineers about how well they can manage the resources applied to the project.

Resource decisions

Debt retirement projects concerned with legacy irreplaceable assets are different from most other projects the enterprise undertakes. Estimates of the labor hours required are more likely to be incorrect on the low side than are analogous estimates for other projects, because so much of the work involves pieces of assets with which few engineering staff have any experience. But with respect to resources, underestimating labor requirements isn’t the real problem. Non-labor resources are the real problem.

Because the assets are irreplaceable, it’s likely that they’re needed for ongoing operations. In some cases, the assets are needed continuously. Many organizations have kept such assets operational by exploiting hours of downtime during periods of low demand, usually scheduled and announced in advance. While these practices are likely sufficient for the relatively minor and infrequent changes usually associated with routine maintenance and enhancement, debt retirement imposes much more severe burdens on the organization than these short access windows can support. Effective debt retirement projects need far more access to the asset—a level of access that continuous delivery practices can provide [Humble 2010].

However, assets whose designs predate the widespread use of modern practices such as continuous delivery might not be compatible with the infrastructure that these practices require. And in organizations that haven’t yet adopted such practices, staff familiar with them might be in short supply. For these reasons, we must regard as developmental any early projects whose objectives are retiring technical debt from irreplaceable assets. They’re retiring the technical debt, of course, but they’re also developing the practices and infrastructure needed to support technical debt retirement projects. This dual purpose is what drives the surprisingly high non-labor costs and investments associated with early technical debt retirement projects.

The investments required might include such “items” as a staging environment, which “is a testing environment identical to the production environment” [Humble 2010]; extensive test automation, including results analysis; blue-green deployment infrastructure; automation-assisted rollback; and zero-downtime release infrastructure. Decisions to make investments require an appreciation of their value to the enterprise. They enable the enterprise to deal effectively with the wicked problem of technical debt retirement.

Last words

Because every situation and every organization is unique, few general guidelines are available for making these decisions. The criteria most organizations have been using for dealing with (or avoiding) the issue of technical debt have produced the problems they now face. So, to succeed from this point, whatever criteria they use in the future must be different. My own view is that short-term thinking is at the heart of the problem, but it’s a wicked problem. The long-term solution will not be simple.

References

[Brenner 2017b] Richard Brenner. “Managing Technical Debt: Nine Policy Recommendations,” Cutter Consortium Executive Update 18:4, 2017.

Available: here; Retrieved: December 29, 2017

Cited in:

[Dragičević 2016] Tomislav Dragičević, Xiaonan Lu, Juan C. Vasquez, and Josep M. Guerrero. “DC Microgrids–Part II: A Review of Power Architectures, Applications and Standardization Issues,” IEEE Transactions on Power Electronics, vol 31:5, 3528-3549, 2016.

Cited in:

[Fowler 2009] Martin Fowler. “Technical Debt Quadrant.” Martin Fowler (blog), October 14, 2009.

Available here; Retrieved January 10, 2016.

Cited in:

[Garnett 2013] Steve Garnett, “Technical Debt: Strategies & Tactics for Avoiding & Removing it,” RippleRock Blog, March 5, 2013.

Available: here; Retrieved February 12, 2017.

Cited in:

[Humble 2010] Jez Humble and David Farley. Continuous delivery: reliable software releases through build, test, and deployment automation, Pearson Education, 2010.

Cited in:

[Meadows 1997] Donella H. Meadows. “Places to Intervene in a System,” Whole Earth, Winter 1997.

Available: here; Retrieved: June 28, 2018

Cited in:

[Meadows 1999] Donella H. Meadows. “Leverage Points: Places to Intervene in a System,” Hartland VT: The Sustainability Institute, 1999.

Available: here; Retrieved: June 2, 2018.

Cited in:

[Meadows 2008] Donella H. Meadows and Diana Wright. Thinking in Systems: A Primer. White River Junction, VT: Chelsea Green Publishing, 2008.

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Cited in:

[Rittel 1973] Horst W. J. Rittel and Melvin M. Webber. “Dilemmas in a General Theory of Planning”, Policy Sciences 4, 1973, 155-169.

Available: here; Retrieved: October 16, 2018

Cited in:

[Weinberg 1985] Gerald M. Weinberg. The Secrets of Consulting. New York: Dorset House, 1985.

Ford’s Fundamental Feedback Formula. Order from Amazon

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Rules of engagement for auxiliary technical debt

As noted in an earlier post, a technical debt retirement project (DRP) is a project whose primary objective is retirement of a particular kind of technical debt—or particular kinds of technical debt—from a specified set of assets. But those assets might also carry other kinds of technical debt. With respect to a given DRP, we can call these other kinds of technical debt Auxiliary Technical Debt(ATD). Because the presence of ATD can defocus debt retirement projects, it presents a risk that must be anticipated and well understood, if it is to be mitigated.

This post explores concepts and approaches for mitigating the risks associated with the auxiliary technical debt (ATD) of a given technical debt retirement project (DRP). As might already be evident, these initialisms (ATD, DRP, and one more to come) can be difficult to keep straight. Here’s a quick guide: T always means Technical, D always means Debt, R always means Retirement, and P always means Project. Also, if you have a pointing device, and you hover the cursor over the first mention of each initialism in each paragraph, your browser displays the expansion of the term. Touch screen users and keyboarders: sorry, I haven’t yet figured out how to help you in an analogous way, so let me know if you have an idea.

The temptation to retire auxiliary technical debt

Guardrails in a track bed as a rail line crosses a bridge
Guardrails in a track bed as a rail line crosses a bridge. The guardrails are the inner pair of rails. The rails outside the inner pair are the running rails. Guardrails (also known as check rails) function to keep the wheels of derailed cars from straying too far from their proper locations. This is a useful risk mitigation function in high-risk geometries such as curves. It’s also advantageous even if the probability of risk events is low, as in this straight section of track. It’s a worthwhile measure when the consequences of risk events are extremely costly, as in this case. A derailment on a railway bridge or in steep terrain can result in rail vehicles falling to the earth below, which can cause them to pull other vehicles with them. Derailments under highway overpasses can also be problematic. Such derailments can result in damage to rail or highway bridge structures, resulting in loss of service for periods extending far beyond the time needed to clear the derailment. For this same reason, guardrails are also used in tunnels and tunnel approaches. Because uncontrolled scope expansion can have such devastating effects, we need policy guardrails to control scope expansion when retiring technical debt from assets that contain auxiliary technical debt.

I’ve been using the term TDIQ—Technical Debt In Question—to denote the kinds of technical debt whose retirement is the objective of a given DRP. The ATD of that DRP, then, is the collection of instances of any other kinds of technical debt, of types differing from the TDIQ of the DRP, and which are present in the assets being modified by the DRP. Notice that the property of being auxiliary technical debt is relative. It’s relative to the objectives of a given DRP. A particular instance of technical debt might be ATD for one DRP, and TDIQ for another DRP, depending on the respective objectives of each DRP. Notice also that the ATD of a given DRP can include several different kinds of technical debt.

Let’s now examine a scenario in which ATD can generate risk for a DRP. In this scenario, we’ll consider only one kind of ATD; call it ATD0.

Suppose that several members of the DRP team undertake work to retire the DRP’s TDIQ in a portion of one of the debt-bearing assets. In performing this work, they encounter some instances of ATD0. Studying these instances of ATD0 carefully, they conclude that “fixing” the ATD0 along with the TDIQ in that portion of the asset would be easier and less risky than leaving the ATD0 in place and attending only to the TDIQ. Let’s call their approach the ATD approach. And let’s say that the TDIQ approach is one in which the team addresses only the TDIQ, and leaves in place the ATD0 and all other ATD it finds.

Compared to the TDIQ approach, the advantages of the ATD approach are fairly clear. After the work is complete, in either approach, the asset must be tested and re-certified. In the TDIQ approach, when a subsequent DRP is chartered to retire ATD0, that second DRP team will need to test and re-certify the asset again when it completes its work. In the ATD approach, we can avoid modifying, re-testing, and re-certifying the asset a second time, if we’ve already retired all instances of ATD0 from the asset. Thus, in the ATD approach we can avoid a second round of modification, testing, and re-certification.

Risks associated with retiring auxiliary technical debt

But the ATD approach also has some serious disadvantages.

Enterprise assets might be left in a mixed state

Unless the team plans to retire all instances of ATD0, then upon completion of the DRP, enterprise assets will be in a mixed state. Some will be free of both the TDIQ and ATD0; some will be free of the TDIQ but continue to harbor ATD0. This non-uniformity can create complications for subsequent maintenance, documentation, testing, training, enhancement, automation assist development, and so on.

Complications in testing and re-certification

If test results for the modified assets indicate the possibility of new defects, the cause might be associated with the TDIQ work, or the ATD work, or both. Resolving any issues in the test results is thus more complicated under the ATD approach than it is under the TDIQ approach. Similar considerations affect re-certification. Thus, there is a risk that the ATD approach will complicate interpretation of test and re-certification results.

Questions about the reliability of technical debt inventory data

As noted in an earlier post, for any given DRP, the DRP team needs to know which assets bear that project’s TDIQ. In the TDIQ approach, any data previously or concurrently gathered about the location of instances of ATD0 remains valid, because the TDIQ approach doesn’t retire any instances of ATD0. However, in the ATD approach, such inventory data must be corrected to account for the retirement of whatever instances of ATD0 are retired in the ATD approach. Thus, if ATD0 inventory data has already been collected, or if it’s being collected in parallel with the DRP, the DRP team must take steps to adjust the inventory data regarding locations of ATD0 as it retires instances thereof. There is of course a risk that this will not occur as needed, which can create problems for any subsequent DRP for which the ATD0 is contained in its TDIQ. This can be especially challenging if there are multiple DRPs in process simultaneously, each working on different TDIQs, potentially in different debt-bearing assets, but all encountering and retiring instances of ATD0.

Unconstrained scope creep

Suppose there is a DRP whose objective is retiring its TDIQ, and that it has decided to also retire some (or all) instances of a particular kind of ATD, say ATD0. Although that activity would represent an expansion of scope beyond retiring the TDIQ, it might be acceptable and it might even be prudent. But as the team undertakes to retire ATD0, it might confront a similar quandary relative to the relationship between the ATD0 and yet another kind of ATD, which we might call ATD1. The DRP team might then decide to expand scope again. And so on. In general, there is no self-evident stopping point for such a chain of scope expansion. In these circumstances, scope creep can become an unmitigated risk, threatening the coherence and focus of the DRP, with consequences for its budget and schedule.

Last words

In some cases, some of the ATD might be so intertwined with the TDIQ that retiring some instances of the TDIQ necessarily retires some of the ATD. And in other cases, leaving the ATD in place severely complicates retiring the TDIQ. In still other cases, leaving the ATD in place leaves the assets in a complex state that makes ongoing maintenance or enhancement work more difficult. In these cases, what I called the ATD approach above is plainly the wiser course, compared to the TDIQ approach.

Policymakers have a role to play here. They can develop guidance for DRP teams to apply as they come upon these difficult situations to help them decide whether to take the ATD approach or the TDIQ approach. The military calls this guidance “rules of engagement,” while politicians call it “guardrails.”

Deciding between the ATD and TDIQ approaches on a whim, or on what feels right at the moment, inevitably leads to a chaos of inconsistency and scope creep. The safest course is to adopt wise policy—rules of engagement—and to adjust them as the organization learns more and more about retiring technical debt from its assets.

References

[Brenner 2017b] Richard Brenner. “Managing Technical Debt: Nine Policy Recommendations,” Cutter Consortium Executive Update 18:4, 2017.

Available: here; Retrieved: December 29, 2017

Cited in:

[Dragičević 2016] Tomislav Dragičević, Xiaonan Lu, Juan C. Vasquez, and Josep M. Guerrero. “DC Microgrids–Part II: A Review of Power Architectures, Applications and Standardization Issues,” IEEE Transactions on Power Electronics, vol 31:5, 3528-3549, 2016.

Cited in:

[Fowler 2009] Martin Fowler. “Technical Debt Quadrant.” Martin Fowler (blog), October 14, 2009.

Available here; Retrieved January 10, 2016.

Cited in:

[Garnett 2013] Steve Garnett, “Technical Debt: Strategies & Tactics for Avoiding & Removing it,” RippleRock Blog, March 5, 2013.

Available: here; Retrieved February 12, 2017.

Cited in:

[Humble 2010] Jez Humble and David Farley. Continuous delivery: reliable software releases through build, test, and deployment automation, Pearson Education, 2010.

Cited in:

[Meadows 1997] Donella H. Meadows. “Places to Intervene in a System,” Whole Earth, Winter 1997.

Available: here; Retrieved: June 28, 2018

Cited in:

[Meadows 1999] Donella H. Meadows. “Leverage Points: Places to Intervene in a System,” Hartland VT: The Sustainability Institute, 1999.

Available: here; Retrieved: June 2, 2018.

Cited in:

[Meadows 2008] Donella H. Meadows and Diana Wright. Thinking in Systems: A Primer. White River Junction, VT: Chelsea Green Publishing, 2008.

Order from Amazon

Cited in:

[Rittel 1973] Horst W. J. Rittel and Melvin M. Webber. “Dilemmas in a General Theory of Planning”, Policy Sciences 4, 1973, 155-169.

Available: here; Retrieved: October 16, 2018

Cited in:

[Weinberg 1985] Gerald M. Weinberg. The Secrets of Consulting. New York: Dorset House, 1985.

Ford’s Fundamental Feedback Formula. Order from Amazon

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Technical debt retirement: where is the technical debt?

When we first set out to plan a large technical debt retirement project (DRP), a question that arises very early in the planning process is this: Which assets are carrying the kind of technical debt we want to retire? And a second question is: Which operations will be affected—and when—by the debt retirement work? Although these questions are clear, and easily expressed, the answers might not be. And the answers are important. So where is the technical debt?

Part of the cutting head of an 84-inch (2.13 m) tunnel boring machine
Part of the cutting head of an 84-inch (2.13 m) tunnel boring machine used for installing a sewer in Chicago, Illinois, USA, in 2014. Photo © 2014 by J. Crocker.

Determining which of the enterprise’s many technological assets might be carrying the Technical Debt In Question (TDIQ) can be a complex exercise in itself, because inspecting the asset might be necessary. Inspection might require temporarily suspending operations, or determining windows of time during which inspection can be performed safely and without interfering with operations. Further, inspection might require knowledge of the asset that the DRP team doesn’t possess. Moreover, access to the asset might be restricted in some way. In these cases, staff from the unit responsible for the asset must be available to assist with the inspection.

Although asset inspection might be necessary or preferable, it might not be sufficient for determining which assets are carrying the TDIQ. This is easy to understand for physical assets, like, say, determining the release version of the firmware of the hydraulic controller electronics of a tunnel boring machine. But asset inspection might also be insufficient for purely software assets. For determining the presence of the TDIQ in software assets, reading source code might not be sufficient or efficient. It might be easier, faster, and more accurate to operate the asset under special conditions. For example, an inspector might want to provide specific inputs to the asset and then examine its responses. As a second example, we might use automation assistance to examine the internal structure of the asset, searching for instances of the TDIQ. And as with other assets, the assistance of the staff of the unit responsible for the asset might be necessary for the inspection.

Which enterprise operations depend on debt-bearing assets?

Knowing which assets bear the TDIQ is useful to the DRP team as it plans the work to retire the TDIQ. But part of that plan could include service disruptions. If so, it’s also necessary to determine how those disruptions might affect operations, to enable the team to control the effects of the disruptions, and negotiate with affected parties. Thus for each asset that bears the TDIQ, we need to determine what operations would be affected if the asset is removed from service temporarily.

Observing actual operations in conditions in which the asset is out of service in whole or in part might be the only economical way to discover which enterprise functions depend on the assets that carry the TDIQ. Other techniques include examining historical data such as trouble reports and outstanding defect lists, and correlating them across multiple asset histories and operations histories.

In some cases, these investigations produce results that have a limited validity lifetime, owing to ongoing evolution of the debt-bearing assets and the assets that interact with them. For that reason, the actual work of retiring the TDIQ must begin as soon as possible after the inventory is complete, and possibly even before that. This suggests that the size of the DRP team is a critical success factor, because size enables the team to complete the inventory inspections rapidly, before the end of the validity lifetime of the team’s research results.

Managing teams of great size is a notoriously difficult problem. For this reason, delegating some of the DRP research effort directly to the business units that own the assets in question can provide the labor hours and expertise needed for the research. In this way, the DRP can deploy a team-of-teams structure, known as a Multi-Team System (MTS) [Mathieu 2001] [Marks 2005]. The DRP team can then bring to bear a large force in a way that renders the overall MTS manageable.

References

[Brenner 2017b] Richard Brenner. “Managing Technical Debt: Nine Policy Recommendations,” Cutter Consortium Executive Update 18:4, 2017.

Available: here; Retrieved: December 29, 2017

Cited in:

[Dragičević 2016] Tomislav Dragičević, Xiaonan Lu, Juan C. Vasquez, and Josep M. Guerrero. “DC Microgrids–Part II: A Review of Power Architectures, Applications and Standardization Issues,” IEEE Transactions on Power Electronics, vol 31:5, 3528-3549, 2016.

Cited in:

[Fowler 2009] Martin Fowler. “Technical Debt Quadrant.” Martin Fowler (blog), October 14, 2009.

Available here; Retrieved January 10, 2016.

Cited in:

[Garnett 2013] Steve Garnett, “Technical Debt: Strategies & Tactics for Avoiding & Removing it,” RippleRock Blog, March 5, 2013.

Available: here; Retrieved February 12, 2017.

Cited in:

[Humble 2010] Jez Humble and David Farley. Continuous delivery: reliable software releases through build, test, and deployment automation, Pearson Education, 2010.

Cited in:

[Marks 2005] Michelle A. Marks, Leslie A. DeChurch, John E. Mathieu, Frederick J. Panzer, and Alexander Alonso. “Teamwork in multiteam systems,” Journal of Applied Psychology 90:5, 964-971, 2005.

Cited in:

[Mathieu 2001] John E. Mathieu, Michelle A. Marks and Stephen J. Zaccaro. “Multi-team systems”, in Neil Anderson, Deniz S. Ones, Handan Kepir Sinangil, and Chockalingam Viswesvaran, eds., Handbook of Industrial, Work, and Organizational Psychology Volume 2: Organizational Psychology, London: Sage Publications, 2001, 289–313.

Cited in:

[Meadows 1997] Donella H. Meadows. “Places to Intervene in a System,” Whole Earth, Winter 1997.

Available: here; Retrieved: June 28, 2018

Cited in:

[Meadows 1999] Donella H. Meadows. “Leverage Points: Places to Intervene in a System,” Hartland VT: The Sustainability Institute, 1999.

Available: here; Retrieved: June 2, 2018.

Cited in:

[Meadows 2008] Donella H. Meadows and Diana Wright. Thinking in Systems: A Primer. White River Junction, VT: Chelsea Green Publishing, 2008.

Order from Amazon

Cited in:

[Rittel 1973] Horst W. J. Rittel and Melvin M. Webber. “Dilemmas in a General Theory of Planning”, Policy Sciences 4, 1973, 155-169.

Available: here; Retrieved: October 16, 2018

Cited in:

[Weinberg 1985] Gerald M. Weinberg. The Secrets of Consulting. New York: Dorset House, 1985.

Ford’s Fundamental Feedback Formula. Order from Amazon

Cited in:

Other posts in this thread