[29athrowaway]

From a task-oriented perspective, developer A can seem more productive than developer B because developer A marked more tasks as finished than developer B.

The problem is that marking a task as finished does not mean that its deliverable is solid. A developer can game the system by leaving technical debt behind for others to fix. In this way, the developer is stealing productivity from others, by forcing them to spend more time reading, debugging, refactoring their half-baked code.

A neophyte manager may buy into this approach to performance, and even encourage it. But after a few iterations of this unsustainable practice of leaving tech-debt behind for no reason, reality sets in: now you need an army of engineers to get things done because the system becomes fragile and complicated. And you also need an endless amount of documentation that is constantly getting out of sync.

In a way, under poor performance management rules, development becomes like a game of pool: it's not only about having a higher score, but also about making it more difficult for others to have a high score. If you want high productivity, recognize this and penalize it.