This book is about a study exploring the relationship between dispositional affectivity and job performance under the potential mediating effects of job satisfaction. The study was conducted in three phases. In Phase I, the scale development phase, a teaching assistant evaluation form (AEF) was developed by collecting job analytic information from teaching assistants (TAs) and critical incidents from faculty members. In the second phase of the study, the pilot study, factor structure of the AEF was examined using principle component analyses. Results yielded two factors underlying the AEF. The first factor was named task performance; the second factor was named contextual performance. In the third phase, the main study, hypotheses were tested by gathering dispositional affectivity and job satisfaction data from TAs, and performance evaluation data from the instructors whom the TAs had worked with during the previous semester. Results indicated that positive affectivity (PA) predicted...