Kaiser-Meyer-Olkin (KMO) and Bartlett’s Test of Sphericity are two commonly used statistical tests in the context of factor analysis, particularly exploratory factor analysis (EFA). They are used to assess the suitability of your data for factor analysis and to determine whether the variables in your dataset are appropriate for extracting meaningful factors. Here’s an explanation of each test:
- Kaiser-Meyer-Olkin (KMO) Measure:
- The KMO measure assesses the sampling adequacy of your data, specifically focusing on whether your dataset is suitable for factor analysis.
- It provides a value between 0 and 1, with higher values indicating better suitability for factor analysis. A KMO value closer to 1 suggests that the variables in your dataset have a high degree of common variance, making them suitable for factor analysis.
- KMO values are often interpreted as follows:
- 0.00 to 0.49: Unacceptable for factor analysis.
- 0.50 to 0.59: Marginal for factor analysis.
- 0.60 to 0.69: Mediocree for factor analysis.
- 0.70 to 0.79: Good for factor analysis.
- 0.80 and above: Excellent for factor analysis.
- If the KMO value is low (indicating poor sampling adequacy), it may be necessary to reconsider the inclusion of variables in your factor analysis or collect additional data.
- Bartlett’s Test of Sphericity:
- Bartlett’s Test of Sphericity assesses whether there are significant relationships between the variables in your dataset. In other words, it tests the hypothesis that the correlation matrix of the variables is an identity matrix (all off-diagonal values are zero, indicating no relationships).
- The null hypothesis for this test is that the variables are uncorrelated or that the correlation matrix is an identity matrix.
- If Bartlett’s Test returns a significant result (typically with a p-value less than a chosen significance level, such as 0.05), it suggests that the variables in your dataset do not form an identity matrix and are suitable for factor analysis.
- In practical terms, a significant Bartlett’s Test is a good indicator that there is enough correlation between variables to justify further exploration via factor analysis.
In summary, KMO assesses the overall sampling adequacy of your data for factor analysis, while Bartlett’s Test checks whether the variables in your dataset are correlated enough to proceed with factor analysis. Both tests are essential preliminary steps to determine whether factor analysis is appropriate for your data or whether adjustments to your dataset should be made before conducting factor analysis.