Does microcredit work? Ask which study

From South Asia·An enduring case

Microcredit spread from Bangladesh on powerful anecdotes of transformation; later randomised trials found modest average effects and few of the promised miracles. Both literatures describe the same loans. They differ in what they can see: the trial measures the average, the anecdote selects the exception.

The concepts this raises

Each of these gives a class a different way into the same case.

EvidenceGrounds of Knowledge
What is offered in support of a claim. Evidence is not the same as proof: it raises or lowers how likely a claim is, and its force depends on how it was gathered, what it was gathered for, and what else it is consistent with. Asking what would count as evidence against a claim is usually more revealing than listing evidence for it.
CertaintyStatus of Knowledge
The degree to which doubt about a claim has been closed off. Certainty is a state of the knower, not of the claim, which is why a claim can be true without anyone being certain of it and why confidence and reliability can come apart badly.

Where it sits in the knowledge framework

Methods and tools
The practices, conventions, instruments and forms of reasoning through which knowledge here is actually made, together with the assumptions those methods build in and what they are structurally unable to detect.

Areas of knowledge

Cases that raise a concept this one raises, but in a different area of knowledge or a different part of the world. That contrast is the point: it is what shows a student the concept travels.