Rater biases are errors in judgment when evaluating others. These include:

  • Halo Effect: the tendency to judge all aspects of the individual based on one factor
  • Leniency Bias: consistently assigning high ratings to everyone
  • Strictness Bias: consistently assigning low ratings to everyone
  • Central Tendency Bias: consistently assigning average ratings to everyone
  • Contrast Effect: the tendency to compare the individual to others rather than the criteria

These biases can be reduced by:

  • avoiding graphic rating scales
  • using the Critical Incident Technique
  • using behavioral descriptions like Behaviorally Anchored Rating Scale (BARS)
  • training the raters