Motherhood and apple pie
A staple of software engineering research is the effectiveness of design reviews and code inspections for discovering defects. Methodologists love inspections, but they seem to be difficult to sustain in practice. I’ve seen a few typical reasons for this:
- Inspection is a specific skill that requires training and discipline. Naive, unstructured “code review” is worse than useless and eventually self-destructs.
- Inspection is quick to be dropped under acute schedule pressure, and slow to restart as a habit once it has been broken.
- Inspection works well for frequent small batches and badly for infrequent large batches.
Reason 1 is a matter of skill, and can be solved with education. Reasons 2 and 3 are process issues.
The “inspection gap” illustrates a curious aspect of human nature. There are certain behaviors that a group of people will agree should be practiced by its members. Individual members of the group, when asked, will say that they believe that members of the group should practice the behavior. But then, in practice, those same individuals do not practice that behavior or practice it inconsistently. If you point this out to them, they may agree that they should do it, or even apologize for not doing it, and then continue to not do it anyway.
In my mind, this is a good part of what Lean thinking has to offer. Lean methods like Visual Control recognize this aspect of human nature and provide people with enough structure and context to act in a way that is consistent with their own beliefs. If people using a Lean process agree that code inspections are a good idea, then it will not be hard to get them to agree to incorporate inspections into the process in a way that is hard to neglect. Lean strives to make it easier to do the right thing than do the wrong thing. Lean helps people align their actions with their values.
One practice that works well in most workflow systems is the simple checklist. Human attention is a delicate thing. People get distracted, make mistakes, and overlook things even when they know better. A checklist is a simple device to keep your intentions aligned with your actions. Doctors who use checklists deliver dramatically improved patient outcomes. Would you get on an airliner with a pilot who didn’t use a pre-flight checklist? Would you get on an airliner controlled by software that was written without using checklists?
Checklists and kanban are highly complementary because you can attach a checklist directly to a kanban ticket and make the checklist part of the completion transaction. Checklists improve confidence and trust, and expose tacit knowledge. Checklists relieve anxiety and reduce fear. Can you think of any part of your development process where you’d sleep better at night knowing that all of the important questions were answered correctly by somebody you trust?
Checklists work well for individual activities that do not require specific sequencing, but they don’t work as well for activities that require collaboration from people who have competing commitments. We can raise the stakes for everybody if we elevate our checklist item to the workflow and subject it to the pull discipline. That makes your problem everybody’s problem and gives your peers sufficient incentive to collaborate.
Inspections are a typical example at the scale of a single developer, but there are other practices and scales that we might consider. Failure Mode and Effects Analysis (FMEA) is another highly effective technique that many people agree with in principle but find difficult to implement in practice. FMEA is a systemic method and often targets components or subsystems that are much larger than “user story” scope . Security lifecycle and regulatory compliance activities may also fall into this category. An advantage of using composite workflow is that you can schedule activities that apply to different scales of work.
Process retrospectives can also be attached to workflow in this way. Compared to a more open-ended periodic retrospective, a workflow-bound retrospective asks a more specific question: How could we have created this work product more effectively? Such a workflow-based retrospective directly implements Deming’s Plan-Do-Study-Act cycle.
Are there any practices you would like to see your team use consistently, but have trouble fitting in to your schedule?