We Knew Fire was Hot
This paper discusses Ludger Woessman鈥檚 research paper on class-size effects in school systems around the world
Abstract
Lant Pritchett looks at Ludger Woessman鈥檚 body of research to emphasise one particular paper of his, written jointly with Martin West, entitled 鈥楥lass-size effects in school systems around the world: Evidence from between-grade variation in Trends in International Mathematics and Science Study (TIMSS)鈥�. When the paper was written in 2002, it already spoke directly to the likely external validity of estimates of causal impact from 鈥渆ducation production functions鈥� relating inputs to learning outcomes. If 鈥渨hat works鈥� is truly heterogeneous across contexts鈥攁nd this Woessmann paper shows that even for simple inputs like 鈥渃lass size鈥� and even in mostly developed country contexts, it is鈥攖hen aggregating estimates of 鈥渨hat works鈥� is not going to be of much use in deciding what to do in specific circumstances.
But Pitchett鈥檚 point is that we already knew that was going to be the case, both empirically and logically. We did not need to spend millions of dollars and hundreds of Randomised Control Trials (RCTs) to know they were not going to add up to a single clear answer about 鈥渨hat works鈥� in any given context. The lack of external validity of the emerging RCT evidence is not a surprise or even a 鈥渇inding鈥� that we could have only reached by doing the RCTs鈥攚e knew the eventual outcome, we just didn鈥檛 want to know it.
This paper is part of the Research on Improving Systems of Education (RISE) Programme.
Citation
Pritchett, L. (2018). We Knew Fire was Hot. Research on Improving Systems of Education (RISE) Programme Insights
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