The present study analyses the prediction of the effectiveness and its fluctuations of 34 semi-professional basketball players throughout a sport season using the dynamic criteria as theoretical framework. The predictor variables (the Big Five personality factors, job experience and motivation) were obtained by means of self-report, while effectiveness was determined through objective data (statistics of matches). The predictive models were developed using generalized maximum entropy formulation, and results show that: (1) the relevance of the predictors of effectiveness is different each time they are analysed; (2) all variables except conscientiousness predict the fluctuations, and openness to experience is the most influential predictor; and (3) job experience is less relevant than personality and motivation. Finally, some recommendations are made regarding the choice of predictors for the selection of basketball players.