A new scale for measuring adults' prosocialness

In the present study, the authors proposed a novel self-report 16-item scale for assessing individual differences in adult prosocialness and tested its measurement properties by employing an item response theory (IRT) analysis of data collected from a sample of 2,574 Italian adults. Prior work employing classical psychometric methods of analysis had already established the reliability and validity of the instrument. The present study furthered this scrutiny by examining whether the different prosocialness items were equally effective in discriminating people and equally informative;. it also examined gender differences in the functioning of the items. The results of IRT analyses strongly supported the measurement effectiveness and sensitivity of the 16 prosocialness items, and findings are discussed for their implications in behavioral assessment research on prosocialness.