Making Sense of Factor Analysis: The Use of Factor Analysis for Instrument Development in Health Care Research

1. An Overview of Factor Analysis Characteristics of Factor Analysis Exploratory Vs. Confirmatory Factor Analysis Assumptions of Exploratory Factor Analysis Historical Developments of Factor Analysis Uses of Factor Analysis in Health Care Research Decision-Making Process in Exploratory Factor Analysis 2. Designing and Testing the Instrument Types of Measurement and Frameworks The Use of Latent Variables in Instrument Development Identifying Empirical Indicators of Latent Variables Using Qualitative Research Methods to Identify Empirical Indicators Additional Qualitative Approaches to Identifying Empirical Indicators Development of the Instrument Scoring the Instrument Pilot Testing the Instrument Determining the Number of Subjects 3. Assessing the Characteristics of Matrices Characteristics and Types of Matrices Tests of Matrices Review of the Process 4. Extracting the Initial Factors Evaluating the Correlation Matrix Sources of Variance in Factor Analysis Models Determining the Factor Extraction Method Selecting the Number of Factors to Retain Comparing the Two-Factor Solution Using PCA and PAF 5. Rotating the Factors Achieving a Simple Structure Types of Rotations Mapping Factors in Geometric Space Orthogonal Rotations Oblique Rotations Comparing the Orthogonal and Oblique Solutions Advantages and Disadvantages of the Oblique Solution Choosing Between Orthogonal and Oblique Rotations Summary of the Process of Rotations 6. Evaluating and Refining the Factors Evaluating and Refining the Factors Assessing the Reliability of an Instrument Evaluating the Internal Consistency of an Instrument Estimating the Effects on Reliability of Increasing or Decreasing Items Cronbach's Coefficient Alpha Assessing Reliability Using Cronbach's Alpha: A Computer Example Two Additional Reliability Estimates: Temporal Stability and Equivalence 7. Interpreting Factors and Generating Factor Scores Interpreting the Factors Naming the Factors Interpreting and Naming the Four Factors on the CGTS Scale Determining Composite Factor Scores 8. Reporting and Replicating the Results When to Report the Results What to Include in the Report An Exemplar of a Published Report Replicating the Factors in Other Studies Conclusions Appendix A: Concerns About Genetic Testing Scale Appendix B: SAS Commands and Generate Output Appendix C: Output for 20-item CGTS Scale Appendix D: Tables for the Chi-Square and Normal Distributions Appendix E: Unraveling the Mystery of Principal Component Extraction References Index About the Authors