A Field Study on Technical Debt

http://blog.sei.cmu.edu/post.cfm/field-study-technical-debt-208

by heidibrayer • 11 years ago

99 76 11 years ago

blog.sei.cmu.edu

bglusman• 11 years ago

Shameless plug: I didn't know about their SonarQube project until I'd built debt ceiling, but while ruby only at the moment, it is an open source attempt to provide some mechanics for defining and tracking some quantified approximation of technical debt. No claims it's perfect of course, but would love more real world feedback and/or feature requests! Also would like to extend it to handle JavaScript analysis as well, ideally through a plug-in architecture that could easily handle arbitrary other languages as well.

https://github.com/bglusman/debt_ceiling

shoo3• 11 years ago

Thanks for sharing this. I'm not working on a ruby project, but if I was, I'd give this a try.

I like how `debt_ceiling` supports `TODO` or `# TECHDEBT` tags.

When I think of technical debt, there are some kinds that don't seem easy to automatically measure: "we made an assumption 6 months ago that turned out to be quite wrong, but we haven't had enough time to go back and rework it yet". This could manifest as poor choices of data structures, or an entire system/subsystem that turns out to be nonsensical given increased understanding of requirements. People who understand the problems can manually tag the code, so it's good to see tool support for these kinds of annotations.

jwrubel2• 11 years ago

Oh very cool! I will check it out.

nernst2• 11 years ago

I like the tool. As for the extensions, I would suggest that in my experience SonarQube has the same ability for extension, and does most of its work in the open. So it might be worth considering turning your project into a plugin (or plugins) for SonarQube?

stevecalifornia• 11 years ago

I have never worked in an environment where new employees didn't show up and declare that the existing infrastructure sucks. Knowing this, I caught myself doing the same thing. Reflecting on it, for me it was a coping mechanism. I was overwhelmed by all the new things and didn't understand why this was setup that way, etc.

The reason I bring this up is I am surprised that architectural choice is overwhelmingly the top technical debt concern. That doesn't seem right. I would expect it to be poor code due to time constraints.

bsder3• 11 years ago

In most places I have been, the infrastructure DOES suck.

First question: "Backups?" followed by "When was the last time you did a restore?"

Second question: "What's your revision control?" For all of my slagging on git and the people who use it, I am thrilled if I hear "CVS" or "Subversion" because it means they're using version control. "git" or "mercurial" tells me I have an team that has some level of clue.

Third question: "Build system?" Good luck. Never yet seen it.

stephentmcm2• 11 years ago

You need to look harder then, we tick all three and even use Gitflow. With back ups used all the time for testing live state locally and a CI 1-click (well 5 or 6 actually...) deploy to Test/Stage/Prod.

x0x0• 11 years ago

where are you working or interviewing?

I think, at least in sfbay, it's safe to assume git. And probably some CI tool. This is true across my personal sample of perhaps 15 companies that I know well enough.

cortesoft• 11 years ago

Are you a consultant? It would make sense that companies that need to hire a consultant for these types of things are the companies that aren't currently doing them.

kyllo• 11 years ago

My favorite right now is pom.xml files declaring dependencies that don't exist in the corporate Maven repository, nor in any public one. Kinda defeats the whole purpose of using Maven if I have to go download jars manually.

Ologn• 11 years ago

First question: "Backups?" followed by "When was the last time you did a restore?"

KDE almost lost hundreds of their git repositories in 2013 because they were not doing backups ( https://news.ycombinator.com/item?id=5432760 ).

ryandrake3• 11 years ago

I took a development job once, where I learned on the first day:

1. No backups. Emergency plan = several older copies of the product's source spread among hard drives of various former employees' systems.

2. No source/revision control. Current version of the product's source code was literally whatever was on the lead developer's hard drive at the moment.

3. No deployment process. When a release had to happen, above mentioned developer would build an EXE out of whatever he had (if it built) and directly deploy it to customers.

4. No dependency management. What versions of vendor-provided libraries do we use? Whatever is on the guy's hard drive. Oh, and they're all binaries because we either lost or can't build the source anymore.

5. No bug tracker. The list of stuff that needed to get worked on was whatever the CEO complained about last. There was no concept of a backlog of existing bugs or technical debt.

6. No documentation. But are you surprised at this point?

7. Setting up an environment to build the code was a manual process that relied on searching through past E-mails for lost tribal knowledge, which basically amounted to: Try different include and library paths until there are no errors. Once built I was greeted with 2500+ compiler warnings... (out of 200 or so C++ files).

Oh, and this software ran in airplanes.

ternaryoperator• 11 years ago

"git" or "mercurial" tells me I have an team that has some level of clue.

If you're judging a team being clued in by the SCM, you're doing it wrong. There are great teams that use SVN, and know-nothing teams that use git.

The measure of clued-in should be how well does a technology match the organization's needs?

hyperman_• 11 years ago

A few years ago we introduced svn in our company, to replace PVCS. After 4 years, we managed to hunt most of our source code down and get it commited somewhere. Now, we have loads of contractors, some good, some bad, most cheap, and almost nobody longer than a few months. After seeing what insane things some of these guys managed to do in subversion, I simply don't dare introducing git: The history rewriting features like rebase in their hands scare the hell out of me. At least with subversion, i know that what's in there stays in there. git is great if you can trust your people, but svn is a better choice in a large political company that does not care about what happens to its code.

And dont get me started on the abuse of backups or build systems.

EliRivers• 11 years ago

It can go too far the other way :)

"What's your revision control?" "Git." fine "And Mercurial." Okay "And SVN. And CVS. Some are hosted locally, some are accounts on Bitbucket and GitHub".

"Build system?" "Cmake. And Scons. Depending on which version of the software you're building. And Make. And some bash scripts."

gfosco• 11 years ago

It just shows how completely subjective it is, and that "technical debt" is becoming an excuse for anything and everything.

tracker12• 11 years ago

I know someone who says all the time that what they want is "The cheapest, fastest (least time to complete), most predictable thing to get something done" and "that if it needs fixing, it can be done when the customer pays for it"

Even green field projects there wind up with significant technical debt in under a year or two.

pjungwir• 11 years ago

As a first-year programmer a project manager said to me, "I've never heard a programmer praise another's code. It's always, 'This is crap!'" So I always try to be slow to criticize. There is a lot of crap, but things might not be as simple as you think. I really believe we should take more time to read and understand before we write. Or think about G.K. Chesterton's fence:

https://en.wikipedia.org/wiki/Wikipedia:Chesterton%27s_fence

You should resist someone who says, "I don't know why this is here, let's get rid of it!" Only get rid of something if you do know why it's there!

nothrabannosir• 11 years ago

You should resist someone who says, "I don't know why this is here, let's get rid of it!" Only get rid of something if you do know why it's there!

I know this is orthogonal, but please try to avoid these situations by commenting code which people might wonder exactly that of, in the future. :(

Joky• 11 years ago

Oh no, I always get rid of stuff I don't know why it's there. Because if it does not break when I run "make check", it's not covered by the testing and it shouldn't have been there in the first place anyway. And if it had a use for someone, but nobody knows, removing it is also a very efficient way to figure out :)

jwrubel2• 11 years ago

Thanks for posting - I hadn't really considered Chesterton's Fence as a technical metaphor but as soon as you posted I immediately thought of a person who has a habit of this very act. I'm adding this term to my lexicon.

InclinedPlane2• 11 years ago

It does suck. Most code sucks. We just get used to it. Doesn't mean it doesn't work, doesn't mean it's not valuable. But it still sucks.

As for architecture being the biggest technical debt problem that should be obvious. Architecture is often the most difficult thing to change after the fact.

jschwartzi• 11 years ago

"Good code" is often a euphemism for understandable code.

Bahamut• 11 years ago

Half of the time, the build system of companies I join is unnecessarily complicated. I often end up simplifying things once I get a handle for how it works, creating nice one command deploys or workflows that don't require chaining multiple things or memorizing a gazillion abstractions. Meanwhile, people often waste lots of times on inefficient build tooling and multiple steps to get to the end goal.

None of the companies I have been at created a good model system (although one came close, the employee responsible left due to the startup acting like a consultancy instead of focusing on a quality product) - this has often bit companies hard as data structures start mutating due to changing API & changing requirements, making certain things such as offline caching more difficult.

Architectural choice tends to roll into poor time constraints since poor time constraints puts even more pressure on the code base when poor architecture is involved.

PopeOfNope4• 11 years ago

Notice that nowhere in the article is there any mention of what a good architectural choice is, nor any mention of the perception of debt in relation to the size of the system[0]. My personal experience with architectural choices is that all of them are great early on when the code base is small. As that code base grows, they all suffer under the weight.

[0]: 100k-1M is a very large range. Kudos to them for filtering out small code bases, but a graph of these perceptions measured against code size would have been helpful.

nernst2• 11 years ago

(author here) We cross-tabbed system age vs perception of amount of TD. There was a moderate association between older systems (> 6 yrs) and more perceived debt.

I did not explicitly look at size as this was not one of the original research questions, but a good point. I suspect older systems will tend to be larger (in the domains we studied, anyway). And your point about arch choices being great "early on" can, I think, be captured in the "system age" variable. I guess I'm trying to think of a system that might be young and yet quite large in LOC.. would be an interesting outlier to look at.

tbrownaw• 11 years ago

1. The system grew alongside the devs' understanding of the problem space. There was never time to change decisions that were later found to be not the best (and the older such a decision is, the harder it is to fix).

2. The problem space changes over time. Either because the outside world changes, or because of scope or scale increases. This means that even good architectural decisions can become bad over time.

Isolated pieces of bad code can be fixes when/if they need to be touched for some other reason. Fixing currently-inappropriate architecture takes a bit more effort.

shoo3• 11 years ago

This is very wise.

You try to make the best architectural decision that you can at the time, with the knowledge and resources you have available. Time passes and you learn new things -- maybe the problem changes, or your understanding of it improves, or your understanding of alternative implementation strategies improves. For whatever reason, you can now imagine a new architecture that would be superior, if only it were implemented to replace the old architecture. Now you have technical debt. This doesn't necessarily mean that the best decision now is to pay off the debt by reworking the architecture -- that depends upon a cost/benefit/opportunity cost analysis.

edit:

Tangentially, there's a pretty interesting presentation by Kevlin Henney titled "The Architecture of Uncertainty" [1]. My poor summary: When designing the initial architecture of a system, Kevlin suggests that the team brainstorm to identify which parts of the system have a lot of uncertainty. Each region of uncertainty then becomes a subsystem. Put interfaces between the subsystems that need to be connected. Hopefully you now have an architecture with stable interfaces, even if individual subsystems need to be completely rewritten during the course of the project.

[1] http://www.infoq.com/presentations/Architecture-Uncertainty

mikekchar2• 11 years ago

The thing that is very frustrating in the "There was never time to change decisions..." bit is that there often is time.

If you are curious about what I mean, I invite you to try a little experiment. For a few weeks (2-4 should be sufficient) tell people, "If you see something wrong with the design, refactor it as soon as you see it. If you need some extra time on your story to compensate for that work, just bring it up at standup and we will modify the sprint commitment".

If your experience is like mine, you will find that the vast majority of people will not refactor the design at all. About 10% of the people will try to refactor something, and will end up trying to rewrite the entire app. They will do more damage than good and will probably give up half way through. If you are lucky, maybe 5% will actually refactor something and be successful.

Because I have tried this many times, I've interviewed people and asked them why they do what they do. For the people who don't refactor, the reason they usually give is: "There is no time to refactor". Which is really odd because they have explicitly been given time. What I have come to realize, though, is that people do not want time; they want absolution of responsibility. If you ask them to make the judgement call, they do the math in their head (unconsciously) and determine that they will be rewarded more and criticised less if they do feature work without refactoring. This forces the decision up to the PM/PGM/BM/BA/Whatever, for whom refactoring has no direct benefit. The result is that refactoring is rarely done, and if it is done it is the result of a large political process.

For the people who try to rewrite everything, training seems to be the overwhelming issue. They pull on a thread and the whole sweater comes apart. For some people in this category, though, giving them carte blanche to decide what to do means that they feel they can finally "do it right". Doing it right in this context means that they can replace all the code that they didn't personally write and therefore don't like. Since everyone on the team only writes a small portion of the code, it means that rewriting everybody else's portion is basically rewriting the app. Again, training seems to help because even if a person's goal is to replace everything, if they learn how to do it piece by piece they can be successful. Also if they do that, they will be required to have many coversations and may eventually learn how to work with others.

Finally, you may get one or two people who naturally know how to refactor well. It is useful to find out who these people are and to encourage them. Unfortunately, this often enrages the "my way or the highway" people. The people who are good at refactoring, if encouraged, will naturally dominate the design of the application. Often these people are suppressed by political means because they are so effective at driving the design. In order to enable these people you will need to make some tough decisions on the business end of things.

makeitsuckless• 11 years ago

I have found the #1 source of architecture/reality mismatches over time being that "business" has deliberately kept developers only partially informed on a "need to know" basis.

To be clear, there was nothing malicious about it, it's just that many stakeholders only give their short term needs as input, not the long term strategy that's discussed behind closed doors in the board room. The big problem here is that non-engineers don't get that some strategies don't simply add to the problem space, but fundamentally change it.

"Why the fuck didn't you tell us sooner?" is one of the most common phrases in software development.

davidgerard2• 11 years ago

Part of this is the fresh-eyes effect. Just having someone new look at things should result in good stuff happening in the first three months.

pmontra• 11 years ago

I remember reading this http://higherorderlogic.com/2010/07/bad-code-isnt-technical-...

According to the author call options are a better metaphor for what we call technical debt but admittedly a more difficult one to understand: anyone who knows what a call option is raise hand.

progmal1• 11 years ago

I am not sure I see the advantage in taking a metaphor that is a little off but understandable and replacing it with one that is more accurate, but very few people understand.

wellpast4• 11 years ago

There are some grievances in codebases that do not come with a huge expense. For example, duplicated code. For another example, overly verbose code. I've seen a lot of new codebases and these are minor nuisances and are pretty easy (i.e., take little time) to cope with. I don't classify these as technical debt because if they cost anything it's always so little.

What costs the most is architecturally unsound code. It's actually not really the code per se, it's the abstractions and how they fit together--very specifically, to what extent the abstractions cohere, to what extent they are coupled, and how narrow are the interfaces. Give me a code base that nails these qualities (narrow interfaces, minimal dependencies) and all else (duplicate code, inelegant code) is in comparison NOTHING to deal with.

So the cost of code is almost entirely related to its _architectural soundness_ (to what degree it's coupled, its interfaces are too wide, etc.)

The biggest and prevelant fallacy of our industry is this notion of technical debt. Because the notion implies that it's somehow necessary. It's not necessary.

The ability to build and evolve architecturally sound code is a function of skillset. If the skillset is there, there is no necessary extra cost. In fact, for people that have this skillset it costs MORE to depart from instincts and couple code, create wide interfaces, etc.

When a developer says 'It will take too long to do the right thing,' (i.e., build architecturally sound code) he/she is saying, 'I don't have the skillset.'

I know all the objections here (it takes time to understand your use cases, etc.), but the objections nearly always miss the fact that architectural soundness and things like code scope/flexibility are ORTHOGONAL properties. You can have very specific code that does very specific minimal-viable product type things ... but this has nothing to do with whether the code is architectural sound or not.

As long as we continue to think of techincal debt as something that's somehow necessary and something to be negotiated we will always be missing the point. The point is that we need to produce workers with the right skillset. There are so few people that have it--which is entirely a failure in our academies, educators, training systems... To keep talking about technical debt and not about how to acquire the architectural skillset is to keep chasing our tails.

philbo• 11 years ago

I don't classify these as technical debt because

Apologies if this is too meta, but that is the most interesting part of your comment for me. It conceals a massive assumption which all devs make, resulting in very different conclusions.

What IS technical debt?

My own preference for the answer is Uncle Bob's description, which is this: technical debt is any production code that does not have (good) tests.

But regardless, any attempts to address technical debt must necessarily begin with a common understanding of what technical debt actually is.

I've rarely seen teams agree that understanding and I think that contributes to their problems.

dragonwriter2• 11 years ago

What IS technical debt?

Any feature of the code or tech stack that increases maintenance/operations cost compared to alternatives.

My own preference for the answer is Uncle Bob's description, which is this: technical debt is any production code that does not have (good) tests.

That's certainly an example of technical debt.

dasil0033• 11 years ago

When a developer says 'It will take too long to do the right thing,' (i.e., build architecturally sound code) he/she is saying, 'I don't have the skillset.'

I'll be charitable and say this may be the case part of the time. But as a general argument it is bollocks. In the vast majority of production systems that survive for any amount of time there will be requirements changes, and sooner or later an engineer will face a choice of shoehorning an attribute in somewhere it doesn't fit naturally, versus refactoring to more appropriately model the new business universe. Saying that this won't happen if your skills are sufficient is a no-true-scotsman argument—it's all tradeoffs, and no matter how good you are at anticipating change, sooner or later even the best architect will be blindsided by some out-of-the-blue business requirement.

wellpast4• 11 years ago

This is the fallacy I was referring to--architectural soundness has nothing to do with anticipating change.

The "choice" your engineer faces to shoehorn a feature in [1] versus implement it in a way that optimizes for soundness (decoupled code w/ narrow interfaces) is not a choice if the skill set is there--i.e., if he/she has trained and practiced the right skill set.

[1] (By 'shoehorn' I assume you mean implement it in a way that leaves the code base in an unsound state.)

brudgers• 11 years ago

There were 39 separate business units represented among the three companies

The context in which this study was done is quite different from an early stage startup. This is not surprising since the SEI tends to focus on big engineering solutions to big problems [which is not to say that its insights and guidance aren't applicable]. But it is important to realize that they focus on engineering in situations that are relatively stable over the long term (29% of systems studied over 10 years old), and almost 1/3 of the systems studied were embedded where changing the software is particularly difficult and throwing more hardware at a problem is not cost effective.

alexbecker• 11 years ago

I can't make heads or tails of the first figure in the post.

nbicdugfeiljij2• 11 years ago

I work in an organisation that has a large technical debt. The organisation manages at least $A60b of member's assets, and is overseen by the Australian Tax Office. It also is very visible politically. These three factors make it extremely conservative in terms of change.

However, change is imposed on it inevitably from the outside, so instead of making large-scale changes to its architecture, it tries to keep up with the market by making thousands of small hacks. The original architecture was not designed to cope with this, so it has become hack upon hack upon hack. I should be employed (and paid above-average) in this jobs for decades to come.

collyw• 11 years ago

Sounds like a system I worked on for an investment bank. Sure you will be employed for years fixing hack upon hack, but its not very rewarding work (in the non financial sense).

zo1• 11 years ago

Don't underestimate the value/reward/fun/etc that you can get from a fresh project. New problems, new development process, the chance to re-iterate past designs and architectures, integration with existing/old/legacy systems, and a host of other things.

That's my bit of advice to you on that, as it reads a bit like you're very comfortable and expecting it to stay that way for "decades to come".

nbicdugfeiljij2• 11 years ago

I do work on my own projects that are fun and interesting. But nothing beats a regular, permanent high-earning job, no matter how boring it is. I personally know a couple of developers who are stressed financially after working for "fun" companies.

A Field Study on Technical Debt

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