Lots and lots of material out there about this type of process in industrial process design circles, a lot of which is suitable for soft production processes like software development.
Plan: Recognize an opportunity and plan a change.
Do: Test the change. Carry out a small-scale study.
Check: Review the test, analyze the results, and identify what you’ve learned.
Act: Take action based on what you learned in the study step. If the change did not work, go through the cycle again with a different plan. If you were successful, incorporate what you learned from the test into wider changes. Use what you learned to plan new improvements, beginning the cycle again.
Presumably the original PDCA has some good if applied correctly - I haven’t studied it, but have heard good things.
I'm not surprised that managers in non-manufacturing/technical areas picked up on it, since it's easy to understand at a glance. However, it's difficult to implement well.
PDCA means basically that you test a change before completely committing to it. That concept is the same as our canary releases, for example, but more clearly, it's the same idea as running one or two iterations of your algorithm on paper before you go and write the program.
It's not some niche thing that is rarely useful, it's just that people try to push it into exactly the work that can't use it.
Anyone that deals with people, no matter what all the training/literature/latest pop-industrial-psychology fad espews.
>PDCA:
Plan (see: "analyze data," i.e. read tea leaves (metrics)): impossible to do with people. Some try to get a "quick glance" via quantitative data, but that doesn't provide you anything practical, except ammo for political moves. People aren't processes. And any attempt to analyze them as a system is the peak of arrogance.
Do: i.e. either go with your gut, allowing your intuition to navigate you, or go with policy/procedure/a process to cover your ass, and check off the "I'm adding value" box, so you can spend your mental energy on other schemes.
Check: see: "Do." Either you know how a certain action/policy affected someone or you have to read "data" to figure it out. Average case, you redefine your metrics and massage the data to get the result you wanted, so...
Act: you can use your results as ammo for political moves. Pat yourself on the back, have your assistant make a spreadsheet, and then hold a 30 minute jerk-off session/meeting with your superiors and fellow sycophants.
Now that I'm really looking at it, this is already implemented by those who deal with people.
But the "innovation" (if that's not too strong of a word) in the nested plan-do-learn loop is that it's explicitly engineered for someone's personal life routine, rather than, say, the development of an external product or service.
Workflowy is great though — years back, I used it for everything. These days I supplement my Notion workflow with Dynalist, which is basically a Workflowy clone with additional features.