Here’s a stylized model of work processes and outcomes. I’m going to call it “Model I”.

If you do work the right way, that is, follow the proper processes, then good things will happen. And, when we don’t, bad things happen. I work in the software world, so by “bad outcome” a mean an incident, and by “doing the right thing”, the work processes typically refer to software validation activities, such as reviewing pull requests, writing unit tests, manually testing in a staging environment. But it also includes work like adding checks in the code for unexpected inputs, ensuring you have an alert defined to catch problems, having someone else watching over your shoulder when you’re making a risky operational change, not deploying your production changes on a Friday, and so on. Do this stuff, and bad things won’t happen. Don’t do this stuff, and bad things will.
If you push someone who believes in this model, you can get them to concede that sometimes nothing bad happens even though someone didn’t do everything can quite right, the amended model looks like this:

Inevitably, an incident happens. At that point, we focus the post-incident efforts on identifying what went wrong with the work. What was the thing that was done wrong? Sometimes, this is individuals who weren’t following the process (deployed on a Friday afternoon!). Other times, the outcome of the incident investigation is a change in our work processes, because the incident has revealed a gap between “doing the right thing” and “our standard work processes”, so we adjust our work processes to close the gap. For example, maybe we now add an additional level of review and approval for certain types of changes.

Here’s an alternative stylized model of work processes and outcomes. I’m going to call it “Model II”.

Like our first model, this second model contains two categories of work processes. But the categories here are different. They are:
- What people are officially supposed to
- What people actually do
The first categorization is an idealized view of how the organization thinks that people should do their work. But people don’t actually do their work their way. The second category captures what the real work actually is.
This second model of work and outcomes has been embraced by a number of safety researchers. I deliberately called my models as Model I and Model II as a reference to Safety-I and Safety-II. Safety-II is a concept developed by the resilience engineering researcher Dr. Erik Hollnagel. The human factor experts Dr. Todd Conklin and Bob Edwards describe this alternate model using a black-line/blue-line diagram. Dr. Steven Shorrock refers to the first category as work-as-prescribed, and the second category as work-as-done. In our stylized model, all outcomes come from this second category of work, because it’s the only one that captures the actual work that leads to any of the outcomes. (In Shorrock’s more accurate model, the two categories of work overlap, but bear with me here).
This model makes some very different assumptions about the nature of how incidents happen! In particular, it leads to very different sorts of questions.

The first model is more popular because it’s more intuitive: when bad things happen, it’s because we did things the wrong way, and that’s when we look back in hindsight to identify what those wrong ways were. The second model requires us to think more about the more common case when incidents don’t happen. After all, we measure our availability in 9s, which means the overwhelming majority of the time, bad outcomes aren’t happening. Hence, Hollnagel encourages us to spend more time examining the common case of things going right.
Because our second model assumes that what people actually do usually leads to good outcomes, it will lead to different sorts of questions after an incident, such as:
- What does normal work look like?
- How is it that this normal work typically leads to successful outcomes?
- What was different in this case (the incident) compared to typical cases?
Note that this second model doesn’t imply that we should always just keep doing things the same way we always do. But it does imply that we should be humble in enforcing changes to the way work is done, because the way that work is done today actually leads to good outcomes most of the time. If you don’t understand how things normally work well, you won’t see how your intervention might make things worse. Just because your last incident was triggered by a Friday deploy doesn’t mean that banning Friday deploys will lead to better outcomes. You might actually end up making things worse.