What are Lesson Learned, Promising Practice and Good Practice?

There can be some confusion around these learning concepts. So let me break each of these terminologies down.

Lesson Learned

One can simply think of a lesson learned in this way, “What would we do differently next time? And what would we do the same?”

A lesson learned can be negative or positive.
Derived from a single context, but applicable to a wider context. Although lessons are derived from a specific situation, they are intended to have wider relevance. As such, “they should specify the context from which it is derived [and] establish its relevance beyond that context. However, lessons are often regarded as one-off findings that lack supporting information from other sources. Lessons that are supported by ‘triangulated’ evidence command greater credibility among their potential users; …” (UNEP 2007)
Must be significant. The lesson learned makes a difference to the intervention when acted upon.
Can manifest at anytime of the Project Management Cycle. LL can occur during and at the end of the development intervention

Promising Practice

One can simply think of a Promising Practice in this way, “What is a successful methodology that shows promise to produce good results?”

Always positive and successful.
It is replicable in a single setting/specific context.
It should be testable.
It should be validated by evidence.
It has the potential to become good practice. However, there is not enough research or replication in the single setting to support wider adoption/upscaling in multiple settings.

Good/Best Practice

One can simply think of a Good Practice in this way, “What is a successful methodology that has produced good results?”

Always positive and successful.
It should be replicable in multiple settings.
It should be testable.
It should be validated by evidence.
It can be recommended as a good model (though not necessarily prescriptive).

So in sum...

Resources

UNEP (2007) Lessons Learned from Evaluation - A Platform for Sharing Knowledge. Special Study Paper Number 2. https://wedocs.unep.org/handle/20.500.11822/184

Rick Davies (2009) Expectations about identifying and documenting “Lessons Learned”. Retrieved from https://mande.co.uk/wp-content/uploads/2009/08/Guidance%20on%20identifying%20and%20documenting%20LL%20vs21.pdf