Joe is a field sales manager for Elmer's Cupcake Co. It is impossible for him to frequently observe his sale staff at work, so he uses a productivity-based performance appraisal system based on units sold per quarter in each territory. In addition to selling, Joe's reps stock shelves, and assist store managers with returns. Joe may need to address when appraising his reps Group of answer choices criterion contamination reliability issues predictive validity issues contrast error criterion deficiency