[w]e still have one researcher claiming that the original study strongly demonstrates a positive social impact of microfinance; another researcher claiming it demonstrates no such thing; and no end in sight, 13 years after the publication of the original study
Bottom line - the leading interpretation of a reputable and important study swung wildly back and forth over the course of a decade, based not on revolutionary reinterpretations but on quibbles over technical details, while no one was able to view the full data and calculations of the original. For anyone assuming that a prestigious journal’s review process - or even a paper’s reputation - is a sufficient stamp of reliability on a paper, this is a wake-up call.
Never put too much weight on a single study. If nothing else, the issue of publication bias makes this an important guideline. (On this note, note that the 2009 Roodman and Morduch paper was rejected for publication; its sole peer-reviewer was an author of the original paper that Roodman and Morduch were questioning.)
If a study’s assumptions, extrapolations and calculations are too complex to be easily understood, this is a strike against the study. Complexity leaves more room for errors and judgment calls, and means it’s less likely that meaningful critiques have had the chance to emerge. Note that before the 2009 response to the study discussed here was ever published, GiveWell took it with a grain of salt due to its complexity (see quote above). Randomized controlled trials tend to be relatively easy to understand; this is a point in their favor.
- Journals should require submission of replication data and code files with final paper submissions, for posting on the journal site. (The Journal of Conflict Resolution is one of the few major political science or economics journals I know that does so faithfully.)
- PhD field and method courses ought to encourage replication projects as term assignments. (Along with encouragements to diplomacy–something new scholars are slow to learn, to their detriment.)