We don’t have that, so we have to go by models, guesstimates, anecdotal personal experience, and expert opinion.
There is some relevant social research on it: https://rtcharity.org/2017-lean-impact-assessment-qualitative-findings/
RCTs, in my view would be unsuited to measuring anything actually useful about groups, however tempting the idea is. There are so many variables muddying the water for such assessment that you would end up just fabricating without realising.
There is some relevant social research on it: https://rtcharity.org/2017-lean-impact-assessment-qualitative-findings/
RCTs, in my view would be unsuited to measuring anything actually useful about groups, however tempting the idea is. There are so many variables muddying the water for such assessment that you would end up just fabricating without realising.