1. Cohen, J.(1988).Statistical Power Analysis for the Behavioral Sciences, 2nd edition. Lawrence
ErlbaumAssociates.
Cohen, J.(1988).Statistical Power Analysis for the Behavioral Sciences, 2nd edition. Lawrence
ErlbaumAssociates.
Promoting Sun Protection: Psychometric Assessment of the Processes of Change Scale for Sun Protection
Marie A. Sillice, Steve F. Babbin, Joseph Rossi, Colleen Redding, Karin Oatley, Kathryn Meier, Wayne F. Velicer
Cancer Prevention Research Center
University of Rhode Island - Kingston, RI
Results
Scale reliabilities:
Factorial invariance was demonstrated for all subgroups, thus, Cronbach’s Coefficient Alpha was calculated for the total sample (see Figure 1 for the Structure of Scale and the corre-lations among factors table ). Coefficient Alpha was .80 for the behavioral processes subscale and .90 for the experiential processes subscale.
Discussion
The overall psychometric properties of the scale indicate that it is a reliable and valid instrument that is invariant across subgroups:
CFI indices were between .90 and .93.
ΔCFI values were below 0.01 for all three models for all subgroups, indicating strong invariance.
Fit indices NFI, NNFI and CFI were consistent for the three models across the subgroups.
RMSEA values were usually below .05 and showed strong fit for each of the three models.
References
Maddock, J.E., Rossi, J.S, Redding, C.A., Meier, K.S., Velicer, W.F. & Prochaska, J.O. (1998). Development of Transtheoretical model constructs for sun protection behaviors among adolescents. Annals of Behavioral Medicine, 20, S208.
Introduction
The increased rate of skin cancers in the
United States, and also worldwide,
represents a major health concern. The
adverse outcomes of skin cancer, which
include death, underlines the necessity for
effective intervention to promote sun
protection behaviors and decrease risks.
Processes of Change For Sun Protection
The Processes of Change Scale for Sun
Protection (PCSSP), based on the trans-
theoretical model, evaluate the experiential
and behavioral strategies for sun protection
behaviors in adolescent and adult populations
(Prochaska et al., 1988).
The scale was modeled as a fourteen-factor correlated model with twenty-eight items: Fourteen items measure the behavioral processes subscale and fourteen items measure the experiential processes subscale (see Figure 1). The behavioral processes represent the strategic use of personal, social, and environmental resources to promote behavior change, and experiential processes represent cognitive and affective experiences or activities to promote behavior change. Participants were asked to report their use of each process from a 5-point Likert scale, ranging from 1 = “Never” to 5 = “Very often.”
Method
Participants:
Sample (N = 1364) adult participants participating in an intervention for exercise and sun protection.
Majority were White (n=1162) and women (n=861).
Modal age was 49 years old.
Development of Subgroups
Subgroups based on demographic variables of age, education, ethnicity, gender, race, skin stone, and stage
of change for sun protection.
Analysis
Factorial invariance was assessed for the subgroups.
Three levels of invariance were evaluated
Configural Invariance,
Pattern Identity Invariance
Strong Factorial Invariance
Four Fit Indices were used:
Comparative Fit Index (CFI),
Normed Fit Index (NFI)
Nonnormed Fit Index (NNFI)
Root Mean Square (RMSEA).
Scale reliability was assessed using Cronbach Coefficient Alpha.
Prochaska, J.O., Velicer, W.F., DiClemente, C.C., & Fava, J.L. (l988). Measuring the processes of change: Applications to the cessation of smoking. Journal of Consulting and Clinical Psychology, 56, 520‑528.