4.1 Lecture
In the social and behavioral sciences we’re often forced to measure key concepts indirectly. For example, we have no way of directly quantifying a person’s current level of depression, or their innate motivation, or their risk-aversion, or any of the other myriad psychological features that comprise the human mental state. In truth, we cannot really measure these hypothetical constructs at all, we must estimate latent representations thereof (though, psychometricians still use the language of physical measurement to describe this process).
Furthermore, we can rarely estimate an adequate representation with only a single observed variable (e.g., question on a survey, score on a test, reading from a sensor). We generally need several observed variables to reliably represent a single hypothetical construct. For example, we cannot accurately determine someone’s IQ or socio-economic status based on their response to a single question; we need several questions that each tap into slightly different aspects of IQ or SES.
Given multiple items measuring the same hypothetical construct, we can use factor analysis to estimate latent variables that represent the unobservable construct. This week we introduce one particular type of factor analysis: confirmatory factor analysis (CFA).
4.1.2 Slides
You can download the lecture slides here.