With engineering focus on reducing incidents and improving operational reliability, I frequently come back to the realization that humans are fallible and we should be learning ways to nudge people toward success rather than failure.

There are whole industries and research machines built around the study of Human Factors, and how to improve safety, reliability, and quality. One topic that struck me as extremely useful to software engineering was the concepts of Work-as-Imagined (WAI) versus Work-as-Done (WAD). Anytime you’ve heard “the system failed because someone executed a process differently than it was documented” could be a WAI vs WAD issue. This comes up a lot in healthcare, manufacturing, and transportation — where accidents can have horrible consequences.

Full disclosure: There are actually many varieties of human work, but WAI and WAD are good enough to make the point. Steven Shorrock covers the subject so well on his blog: Humanistic Systems 

Work-as-Imagined

When thinking about a process or set of tasks that make up work, we need to imagine the steps and work others must do to accomplish the tasks. We do this for many good reasons, like scheduling, planning, and forecasting. WAI is usually formed by past experiences of actually doing work. While this is a good starting point, it’s likely the situation, assumptions, and variables are not the same.

To a greater or lesser extent, all of these imaginations – or mental models – will be wrong; our imagination of others’ work is a gross simplification, is incomplete, and is also fundamentally incorrect in various ways, depending partly on the differences in work and context between the imaginer and the imagined. — The Varieties of Human Work

Work-as-Done

Work-as-Done is literally the work people do. It happens in the real world, under a variety of different conditions and variables.  It’s hard to document WAD because of the unique situation in which the work was done and the specific adjustments and tradeoffs required to complete the work for a given situation.

In any normal day, a work-as-done day, people:

• Adapt and adjust to situations and change their actions accordingly
• Deal with unintended consequences and unexpected situations
• Interpret policies and procedures and apply them to match the conditions
• Detect and correct when something is about to go wrong and intervene to prevent it from happening

Mind the Gap

Monitoring the gap between the WAI and the WAD of a given task has been highlighted as an important practice for organizations aiming to achieve high reliability. The gap between WAI and WAD can result in “human error” conditions. We frequently hear about incidents and accidents that were caused by “human error” in a variety of situations:

• Air traffic near misses at airports
• Train derailments and accidents
• Critical computer systems taken offline
• Mistakes made during medical procedures

It’s natural for us to blame the problem on the gap — people didn’t follow the process — and try to improve reliability and reduce errors by focusing on stricter adherence to WAI. Perhaps unsurprisingly, this results in more rules and processes which can certainly slow down overall productivity, and even increase the gap between WAI and WAD.

Safety management must correspond to Work-As-Done and not rely on Work-As-Imagined. — Can We Ever Imagine How Work is Done?

In recent decades, there is more focus on WAD. Examining the reasons why the WAD gap exists and working to align WAI more closely with WAD. Embracing the reality of how the work is done and working to formalize it. Instead of optimizing for the way we imagine work is done, we acknowledge the way work is actually done.

Closing the Gap

In my work, production incidents that occur in software systems are an easy area to find WAI vs WAD happening. Incident management and postmortems have best practices that usually involve blameless reviews of what led to the incident. In many case, the easiest answer to “how can we stop this incident from happening again?” is better documentation and more process.

Modern incident management is focusing more on learning from incidents and less about root-cause analysis. One reason is that incidents rarely happen the exact same way in the future. Focusing on fixing a specific incident yields less value than learning about how the system worked to create the incident in the first place. Learning about how your system work in production is harder, but yields more impact in discovering weak parts of the systems.

This section could be an entire book, or at least several posts, so I’ll leave it to you to read some of the links.

Desire Paths

The whole WAI vs WAD discussion reminds me of desire paths, which visually show the difference between the planned and actual outcomes.

Desire paths typically emerge as convenient shortcuts where more deliberately constructed paths take a longer or more circuitous route, have gaps, or are non-existent

Tying together desire paths with WAI & WAD, some universities and cities have reportedly waited to see which routes people would take regularly before deciding where to pave additional pathways across their campuses and walking paths.