What is Exploratory Factor Analysis?
Exploratory Factor Analysis (EFA) is a statistical technique used to uncover the underlying structure or patterns in a dataset, particularly when dealing with a large number of variables. It aims to identify the underlying factors that explain the correlations among observed variables.
Here’s how exploratory factor analysis works:
- Data Preparation:
- EFA typically begins with a dataset containing multiple observed variables (e.g., survey items, test scores).
- Factor Extraction:
- The goal of factor extraction is to identify a smaller number of underlying factors that explain the correlations among the observed variables. Commonly used methods for factor extraction include principal component analysis (PCA) and common factor analysis.
- Factor Rotation:
- After extracting factors, factor rotation is often performed to simplify the interpretation of the results. Rotation techniques (e.g., varimax, oblimin) reorient the factors to maximize interpretability, often resulting in clearer patterns of factor loadings.
- Factor Interpretation:
- Once factors are extracted and rotated, researchers interpret the meaning of each factor based on the variables that load most strongly on that factor. Factors represent latent constructs or dimensions underlying the observed variables.
- Assessment of Model Fit:
- While exploratory factor analysis does not involve formal hypothesis testing, researchers often assess the goodness of fit of the model to the data using various indices and criteria, such as the Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy and Bartlett’s test of sphericity.
Exploratory factor analysis is widely used in various fields, including psychology, sociology, education, and health sciences, to explore the underlying structure of complex datasets and to identify latent variables or constructs that may not be directly observable but are reflected in the observed variables.
It’s important to note that EFA is an exploratory technique, meaning it is used for generating hypotheses and uncovering patterns in the data. Confirmatory Factor Analysis (CFA) is another technique used to test and confirm a hypothesized factor structure based on theoretical considerations.