What is Factor Analysis??? Factor analysis is a statistical technique, the aim of which is to simplify a complex data set by representing the set of variables in terms of a smaller number of underlying (hypothetical or unobservable) variables, known as factors.
Types of Factor Analysis – There are basically two types of factor analysis: Exploratory Factor Analysis & Confirmatory Factor Analysis
Exploratory factor analysis (EFA) attempts to discover the nature of the constructs influencing a set of responses. It is exploratory when you do not have a pre-defined idea of the structure or how many dimensions are in a set of variables.
Uses of Exploratory factor analysis-
- To determine what sets of items hang together in a questionnaire.
- To determine what features are most important when classifying a group of items.
- For Psychometric instrument development
Confirmatory factor analysis (CFA) tests whether a specified set of constructs is influencing responses in a predicted way. It is confirmatory when you want to test specific hypothesis about the structure or the number of dimensions underlying a set of variables (i.e. in your data you may think there are two dimensions and you want to verify that).
Uses of Confirmatory Factor Analysis-
- To test whether a set of factors are correlated or uncorrelated
- For social research in developing tests such as intelligence test and personality test
Similarities between Exploratory and Confirmatory Factor Analysis
- Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) are two statistical approaches used to examine the internal reliability of a measure.
- Both are used to assess the quality of individual items.
- Both techniques assume a normal distribution.
Differences between Exploratory and Confirmatory Factor Analysis
- CFA requires that a particular factor structure be specified, in which the researcher indicates which items load on which factor. EFA allows all items to load on all factors.
- CFA requires specifications of the number of factors whereas EFA determines the factor structure.
Sources: http://www.stat-help.com/factor.pdf
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