Internal consistency, factor structure, and concurrent validity of the treatment evaluation inventory

Area of Science:

• Psychometrics
• Health Psychology
• Behavioral Science

Background:

• The Treatment Evaluation Inventory (TEI) is a widely used 19-item scale assessing treatment acceptability.
• It is designed to provide a total score and scores for Patient Progress and Acceptability subscales.

Purpose of the Study:

• To evaluate the internal consistency and factor structure of the Treatment Evaluation Inventory (TEI).
• To assess the concurrent validity of the full TEI scale against other treatment acceptability measures.
• To determine the utility of the TEI's subscales.

Main Methods:

• Internal consistency and factor analysis were conducted on two samples (general public and dental students).
• Score distributions and correlations with alternative acceptability measures were examined in a third sample (undergraduate students).
• The TEI was compared with a thermometer rating scale and a 5-point Likert-type scale.

Main Results:

• The TEI total scale and both subscales demonstrated very high internal consistency across samples.
• Factor analysis revealed a two-factor solution that did not align with the existing Patient Progress and Acceptability subscales.
• The full TEI scale exhibited large, significant correlations with other measures, supporting its concurrent validity.

Conclusions:

• While the TEI demonstrates strong internal consistency and concurrent validity for its full scale score.
• The subscales of the TEI do not meet criteria for independent and useful measures.
• It is recommended that only the full TEI scale score be utilized in research and clinical practice.