Rater bias can be referred as when people evaluate someone or something, all their evaluations reflect the person being assessed and the personal biases of the person who evaluates it. As humans our judgment about different things are affected by our own perceptual knowledge. Bias when becomes bigger and bigger, it results in the evaluation being general, vague and abstract.
Rater bias becomes a big issue when the managers have to rate their employees using scales that are highly subjective or vague. Biases can lead to inflation or deflation of the employee ratings. Different managers apply different biases and their effects are majorly unpredictable. Managers must identify their possible evaluation biases and try to eliminate them.
Following are few rater biases:-
1. Severity- The evaluator tends to avoid giving ratings that are highly positive.
2. Horns- An individual having one negative attribute which causes the evaluator to rate more negatively.
3. Halo- The person has one very positive attribute which cases the evaluator to rate more positively than deserved.
4. Stereotyping- The person being evaluated is perceived to belong to a particular group. The evaluator assumes that the individual being evaluated possess certain stereotypic traits that belong to a particular group.
5. Leniency- The person who evaluates tends to evaluate everyone positively.
6. Similarity- The person being rated shares some similar attribute with the evaluator.
7. Regency- The evaluator remembers something good that has happened to him recently because of the employee that is to be rated and then rates him accordingly, without considering the employees performance.
8. Negative Event – The evaluator still considers the negative event of the person who is to be evaluated even after a long time has passed.
9. Comparison – The evaluator rates on the basis of comparison between the employees of the organization, instead of evaluating the performance of the employee who is to be evaluated.