Review of the psychometric properties of the assertiveness scale in a sample of Mexican adults

Abstract

Assertiveness is understood as the ability to express feelings and thoughts directly and honestly, and its absence is associated with mental health problems such as anxiety and depression. To review the psychometric properties of the assertiveness scale in a sample of Mexican psychologists. A quantitative, non-experimental, cross-sectional study was conducted with 1,242 participants, mainly psychologists and adults from a non-clinical population. An adapted version of the Rathus Assertiveness Scale with 22 items was used. The reliability of the scale was assessed with an overall Cronbach's alpha of .818 and McDonald's ω of .782 both considered acceptable. However, the coefficients by specific dimensions were low (e.g., Manifestation of Feelings = .512, Efficacy = .491, Expression of Opinions = .442), indicating possible internal consistency issues in these subscales. Six main factors were identified, explaining 46.52% of the total variance. These factors include the ability to show disagreement, manifestation of feelings and thoughts, self-efficacy, social interaction, expression of opinions, and the ability to say no. The Construct validity indicated that there were no significant internal consistency problems. Construct validity indicated that the absolute fit and parsimony measures of the model were adequate (Chi-square = .001, RMSEA = .025, CFI = .956, TLI = .948, AIC = 605.769, PRATIO = .861, PNFI = .78). The results are consistent with previous studies conducted in other populations and cultural contexts. The scale proved to be valid and reliable, suggesting its usefulness for assessing assertiveness; however, additional revisions are required by dimensions, as these show low reliability.