Regarding the processes of change, one of the core constructs of the transtheoretical model of intentional behavior change (TTM), extensive research has been done in the field of smoking. However, little is known about the processes of change for alcohol misuse and their measurement. This study's goals were to investigate the psychometric properties of the German Processes of Change (POC) scale and to refine a short version.
Method: A sample of 653 non-treatment seeking general hospital patients with alcohol problems was used. Construct validity of the POC was analyzed using confirmatory factor analysis. As another validity aspect the use of processes of change across the stages of change was investigated.
Results: Internal consistency of the POC-20 ranged between r=.57 and .94. Construct validity was also good (CFI=.94). In line with TTM postulates subjects in later stages reported more behavioral processes compared to individuals in earlier stages.
Conclusion: Findings indicated superiority of the POC-20 over the long version and good validity of the measure in a high per capita consumption nation.