Sunday, February 22, 2015

Triage may seem cruel, but in could save your product

Triage is a term from the battlefield. To be more specific from the battlefield mobile hospitals.

So triage should not have a place in the – comparatively peaceful – world of software development. Or should it?

Sometimes you can’t get them all

It’s all about the question of how to make the best use of your resources in times when the demand exceeds the resources.

The original idea behind triage was to categorize the wounded into three categories (as described more closely in the wikipedia article on triage)

  • Those who are likely to live, regardless of what care they receive
  • Those who are likely to die, regardless of what care they receive
  • Those who would die if they did not receive immediate care but are likely to live if the do get immediate care

and then concentrate your resources on the category where your effort really makes a difference. In the original case this means to start with the third category – cruel though it may seem for the other two categories.

Over the course of time the rationale and theory behind triage have evolved immensely, as can be seen in the article. Both the ethics and the practical application have been refined, but the basic idea is stimm the same. Don’t waste your energy on “lost causes” when that would lead to loosing causes you have a chance of rescuing.

What’s that got to do with software development?

In our day to day work we’re often confronted with situations where the requirements exceed our capacity.

If we try to do everything, even if we dynamically reschedule according to priority, some things won’t get done. That is exactly what “requirements exceed capacity” means. And this is exactly where triage fit’s into the model. If only 4 of 11 requirements will “survive” make sure not to waste any effort on those, that will never see the light of day anyway. Put them in a separate “folder” and once you’ve got discretionary time on your hands revisit that folder and check which of the requirements would still provide value.

If we concentrate on the 4 most important requirements first – the amount we can expect to complete – we end up wit only 36% (4/11) of the requirements fulfilled, but the features for those four requirements can be shipped.

But it is never a good idea to try to fulfill all 11 requirements with only enough resources for 4 – we would end up with 11 requirements fulfilled to 36%. And because a feature that is only 36% complete in most cases is not shippable we would end up with zero deliverable features.

No, it does not mean you can skip tests or refactoring

So if we have to cut functionality can’t we go faster by skipping unit test, documentation or refactoring? That would be just silly – just as if the doctors in the battlefield hospital would omit washing their hands as Uncle Bob would probably remark. On the contrary. Applying triage on a requirement level should give you the time and space to work at your optimum on those requirements that can survive.

till next time
  Michael Mahlberg

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