Purpose: This study seeks to examine the effects of a "personal effectiveness" training on both assertiveness and Psychological Capital (PsyCap) that were monitored before and after the training. Design/methodology/approach: In addition to self-ratings, other-ratings were assembled to explore two ways in which they can contribute to the monitoring of intervention effects. To verify self-reported results, and to predict participants' performance through the use of self-other agreement. Findings: Overall, rater and ratee scores showed a similar increase on assertiveness and most components of PsyCap. Self-other agreement measures showed an increase in agreement for assertiveness and PsyCap after the training. Lastly, the type of relationship between rater and ratee appeared to have significant influence on the consistency between raters, such that agreement was higher for cohabiting partners than colleagues, supervisors or friends. Originality/value: This study has created a better understanding of the role that the self-other agreement and PsyCap can play in monitoring intervention effects. (Contains 10 tables.)