Code Quality: Hidden Costs, Unexpected Benefits

I spend a lot of time thinking about why there's so much bad code in the world, and what we can do about it. I hypothesize two reasons code quality tends to degrade:

• The costs of poor code quality are hard to see, because of how quality shapes decisions at the organizational level.
• Executives and managers don't have the detailed knowledge they'd need to reap the benefits of good code. A strictly command-and-control organization can't take advantage of code quality; teams and individuals need local agency. Such an organization has little reason to prioritize code quality, and little hope of doing so effectively.

These certainly aren't the only two causes of bad code, but they're the ones I'll focus on in this post.

Hidden Costs

Imagine you have two computers: an old clunker, and a new, top-of-the-line machine. The reason you keep the old computer around is that it runs business-critical software that would be too difficult to port to the new computer. Still, you try to touch it as little as possible, doing most of your work on the new computer.

The old computer is slow and annoying to use. When you're using it, it feels like it's costing you a lot of time. However, when you look objectively at how much time you're actually spending with it, you realize it's not actually that much time, in the scheme of things. You touch the old computer so infrequently that the inefficiencies don't add up to much.

Now, here's the thing: if the old computer were faster and easier to use, you'd use it more. You use it infrequently because it's inefficient. The behavior of the larger system (you plus the two computers) has adjusted to accommodate the relative efficiencies of each subsystem.¹

Software companies operate similarly. When a part of the codebase gains a reputation for being legacy code, everyone tries to find ways to avoid touching it. Shims are inserted; substitutes are devised. Whenever possible, behavior is implemented somewhere else.

This leads to a vicious cycle: avoidance of legacy code leads to weird architectural decisions in other parts of the codebase, turning them into legacy code too. But the process is gradual. In the meantime, software development can continue, and the company can keep making money.

More perniciously, bad code directs attention and effort away from certain opportunities. If a feature or product doesn't "pencil out" — if the cost of implementing it would be impractically high, due to poor code quality — then it will never get worked on. In this situation, the cost of changing the bad code will never be paid, but the potential value of the feature won't be realized either.

So it's not that poor quality has no cost. The costs are simply invisible, because they show up as a decrease in value rather than an increase in expenses. How do you measure the cost of not working on code, of not building a feature, because it would be too expensive or risky to try? How do you even notice it? The problem is made worse because working in this kind of environment for a long time can cause a kind of learned helplessness, where you don't even see the opportunities that are available to you.

What's a responsible engineer to do in such a situation? Follow the Scouts' rule: no matter what code you're working on, leave it better than you found it. Or at least, don't make it worse. Although remediating the bad code now might not make economic sense, preventing it in the past would have (if only we had a time machine). We can't undo those past decisions, but we can start making better ones.

Unexpected Benefits

A few months ago, Kent Beck wrote an executive summary of his book Tidy First, titled "The Surprise Factory." The idea of the Surprise Factory is that tidy code produces delightful surprises, in the form of unexpected opportunities to add value to the company. (Kent later decided that "surprise" had too many negative connotations, so he changed the name to "The Gift Factory.")²

Here's the problem that arises when this theory meets practice: although high code quality does produce opportunities to add value, executives can't see which specific opportunities are present. Code quality is not a scalar value; "good code" cannot make every imaginable change equally easy.³ Rather, we call code "good" when it can meet the specific demands placed on it. But executives aren't looking at the code, and can't see which specific demands it might be capable of meeting. The opportunities presented by the Surprise Factory are thus invisible to them.

Without a detailed understanding of the code, executives and managers only have a few crude knobs to turn: one knob might be labeled "more ambitious / less ambitious". Another knob might adjust which parts of the codebase or the product receive the most development effort.

The crudeness of these controls all but ensures that code quality will degrade over time. If executives respond to a high-code-quality, high-opportunity environment by simply turning up the "ambition" knob and directing effort toward the highest-quality parts of the codebase, the code will be ruined by developers trying to hit deadlines: it's unlikely that the opportunities coming out of the Surprise Factory will align perfectly with the the plans that trickle down from the executives' vision. But turning the knobs the other way would be folly: you'd burn out your programmers by making them work on the cruftiest code, and you'd have little to show for it in the end.

Again, what's a responsible engineer to do in this situation? I've come to the conclusion that it's my job to reveal value-adding opportunities to my employer, so they can take advantage of the surprise factory. I do this in a few ways:

• I suggest features that I think would be easy and valuable to add.
• When my team is estimating stories, I point out cheaper alternatives to the proposed design.
• I make delivery forecasts based on data, not vibes.⁴
• I cut out low-value work where possible.

One caveat to this recommendation: in order to pull it off, you need design and product skills as well as engineering skills. Nothing's more annoying than a programmer who won't shut up about the weird feature or design idea that they want to shove into the product. However, it seems that the recent trend is for engineers to take on more design and PM responsibilities anyway — gone are the days of PMs writing Gherkin and designers insisting on pixel-perfection. For better or for worse, we programmers have the power now. We should learn to wield it.