Resumen de Getting it (approximately) right (and center and left!): Reliability and uncertainty estimates for the comparative manifesto data
Michael D. McDonald, Ian Budge
The extensive estimates of party policy preferences produced by the CMP (Comparative Manifesto Project, now MARPOR) have proved robust and valid over a wide variety of research applications. But all estimates carry some error. We demonstrate that one of the two existing assessments of non-systematic error in the CMP data strongly overstates their reliability while the other understates it, leaving much potential for mis-estimation. We develop a new method which extends classical test theory and directly estimates overall data reliability; reliabilities and standard errors of measurement for each party system; and standard errors of measurement for each data-point. These should facilitate use of the CMP policy scores which are usually the only ones available for extended party and policy research.
