Attenuation, Correction for

Charles Spearman noted that many variables, specifically those used in fields such as psychology and sociology, are measured using imperfect approximations. For example, a psychologist might be interested in understanding how cognitive ability is related to performance. The latent construct of cognitive ability could be measured in a number of different ways (e.g., Wonderlic Personnel Test; SAT). Likewise, the latent construct of performance could be measured in a number of different ways (e.g., the number of publications or patents generated by scientists, the overall GPA of undergraduate students). After selecting measurement devices and collecting data, the psychologist can correlate scores on the measure of ability (e.g., SAT) with scores on the measure of performance (e.g., GPA). However, because all measurement systems are subject to random ...