I have a paper that can help answer this, which uses JPAL and IPA studies! However, you might think observational study overestimates come from selection bias during the publication process—our result doesn’t say anything about that.
“First, we find that there is little bias on average. Using our
best-performing observational method (DDML), there is a statistically insignificant and modest
negative mean bias of −0.025 standard deviations. This implies that observational studies do not
systematically over- or underestimate the welfare impact of the programs they evaluate.”
I have a paper that can help answer this, which uses JPAL and IPA studies! However, you might think observational study overestimates come from selection bias during the publication process—our result doesn’t say anything about that.
https://www.jondequidt.com/pdfs/Lalonde30.pdf
“First, we find that there is little bias on average. Using our best-performing observational method (DDML), there is a statistically insignificant and modest negative mean bias of −0.025 standard deviations. This implies that observational studies do not systematically over- or underestimate the welfare impact of the programs they evaluate.”