Job performance is measured by objective rating performance and subjective ratings. Although the former is better than subjective ratings, most of studies in job performance and GCA have been based on supervisor performance ratings. This rating criteria is considered problematic and unreliable, mainly because of its difficulty to define what is a good and bad performance. Rating of supervisors tends to be subjective and inconsistent among employees. Additionally, supervisor rating of job performance is influenced by different factors, such as halo effect, facial attractiveness, racial or ethnic bias, and height of employees. However, Vinchur, Schippmann, Switzer and Roth (1998) found in their study with sales employees that objective sales performance had a correlation of 0.04 with GCA, while supervisor performance rating got a correlation of 0.40. These findings were surprising, considering that the main criteria for assessing these employees would be the objective sales.