Performance appraisal is defined as the systematic review and evaluation of an employee's job performance and the provision of feedback. While the goal is for performance appraisals to be objective, human biases and perceptions can distort the process. Research on performance appraisals focuses on questions such as what is the best rating format to measure performance and how much rater errors and biases affect the process. Modern issues examined in performance appraisal research include the importance of social context factors like relationships and politics, as well as moving away from a focus only on rater errors and towards a greater understanding of the entire appraisal process. Some studies have also started investigating how performance appraisal systems may differ across cultural contexts.