Examining the theory of planned behavior applied to condom use: A comparison of the effect-indicator vs. causal-indicator models

Abstract

The theory of planned behavior was developed by Ajzen & Fishbein (1980) in an attempt to explain a number of health behaviors such as smoking, diet and exercise behaviors, diabetic management, and condom use (Glanz, Rimer, & Lewis, 2002). The theory of planned behavior asserts that actual behavior is a function of the intention to act. Intention, in turn, is a function of the weighted sum of attitudes toward the behavior, subjective norms about the behavior, and volitional control over the behavior. These global components were addressed, as well as their differentiated components. Two conceptually different augmentations of the theory, a causal-indicator model applied to the theory of planned behavior and an effect-indicator model applied to the theory of planned behavior were discussed and compared. Using the intent to use condoms as the extraneous dependent variable, both augmentations were evaluated by model fit indices in a structural model analysis. It was expected that the effect-indicator model would allow for the best-fitted explanation of the theory of planned behavior. The major hypothesis was supported through evaluation of the observed data. Thus, the effect-indicator model was found to be the most satisfactory conceptualization. Adolescent interventions that are driven by the theory of planned behavior may benefit from such a framework by focusing on behavior change with regard to the theory’s global and differentiated components as modeled by the effect-indicator model.