To ensure that your results are valid, consider the following guidelines when you collect data, perform the analysis, and interpret your results.
- You should have at least two variables
- Measurements for each variable should be recorded in separate numeric columns. Alternately, you can enter a stored correlation matrix or a stored covariance matrix, as well as stored factor loadings from a previous analysis.
- You should have at least three variables for each underlying factor
- Generally, you should not have more than one factor for every 3 variables in your data. For example, if you have 12 variables, you should extract, at most, 4 factors.
- Groups of variables should be highly correlated
- For the analysis results to be useful, groups of variables should be highly correlated, with small correlations among variables from different groups.