PSY 2116 Lecture Notes - Lecture 4: Classical Test Theory, Item Response Theory, Abraham De Moivre

• School: University of Ottawa
• Department: Psychology
• Course: PSY 2116
• Professor: Kenneth Campbell

Document Summary

Instead of rigid yardsticks, researchers use rubber yardsticks these may stretch overtime and shrink (measure characteristics) Serious measurement error occurs in most physical, social, and biological sciences. Abraham de moivre introduced the basic notion of sampling error. Karl pearson developed the product moment correlation. Reliability = these 2 concepts put together. Cronbach developed methods for evaluating many sources of error in behavioural research. Item response theory has taken advantage of computer tech to advance psychological measurement: built on ideas of spearman. Difference between true score and observed score results from measurement error. In symbolic representation, the observed score (x) has 2 components; a true score (t) and error component (e: x = t + e or x t = e. Major assumption in classical test theory = errors are random. Might not want to rely on single observation b/c it might fall far from the true score.