Development of a Quality Measure for Adults with Post-Traumatic Stress Disorder. C. Confirmatory Factor Analysis


To further refine the scales identified in the EFA, we conducted CFAs on the five-factor model separately for the clinician, supervisor, and client samples. The CFA models fit the data well and had a similar factor structure across the different respondents (Appendix H, Table H.2), suggesting that the instrument may function similarly across the three types of respondents. Detailed CFA results by respondent type are available in Appendix I. A summary of the commonalities and differences in the factor structures across the samples is below:

  • Factor 1: Structuring and conducting the therapy session. The number of items that compose Factor 1 varies by respondent type. Across the three samples, five items related to agenda setting, goals, treatment process and expectations, and treatment feedback make up this factor. In the clinician and supervisor surveys, this factor also comprises reviewing agendas and being directive. Outlining the treatment process and symptom assessment also loaded on Factor 1 in the clinician and client surveys.

  • Factor 2: Psychoeducation and therapeutic techniques. The items that compose Factor 2 are nearly identical across the three samples and, as previously described, focus on therapeutic techniques such as the use of Socratic questioning and cognitive restructuring.

  • Factor 3: Therapeutic alliance. The three therapeutic items compose Factor 3 across all three samples.

  • Factor 4: Assessment. This factor has only one item, suicide risk assessment "today," shared between the three samples. Each paired sample (clinician/client, clinician/supervisor, client/supervisor) has common items that make up this factor. The items include therapeutic techniques and additional assessment questions.

  • Factor 5: Homework. The items that compose Factor 5 are nearly identical. It has four common items across the three samples and five common items between the clinicians and supervisors.

Summary. Taken together, the EFA and CFA results suggest that the survey items measure constructs relate to the delivery of psychotherapy for PTSD. For further instrument development, we recommend analyzing whether core items that are consistent across all three samples are sufficient to capture the corresponding latent factors without sacrificing the reliability of a scale. This could help to shorten the measurement instrument and decrease the burden for respondents while retaining essential measurement properties. We also recommend considering modifications to the fourth factor, which only has one item shared by all three samples and which also has the lowest scale reliability of all five factors.