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Two methods of constructing equal-interval scales for educational achievement are discussed: Thurstone's absolute scaling method and Item Response Theory (IRT). Alternative criteria for choosing a ...

Background: Clinical trials are commonly done without blinded outcome assessors despite the risk of bias. We wanted to evaluate the effect of nonblinded outcome assessment on estimated effects in ...

A behind-the-scenes blog about research methods at Pew Research Center. For our latest findings, visit pewresearch.org. Pew Research Center has a long history measuring the public’s knowledge about ...