In appointment procedures, there are in particular two phenomena which can influence the decision about candidates in a gender-relevant way: gender bias and homosocial co-optation. Against this background, actors in appointment procedures also have the responsibility to check their personal decision-making behavior and that of the appointment committee to see whether the candidates have been assessed in a gender-sensitive way and whether the best have been found for the appointment list.
In the general use of English language, a bias is regarded as a distorted perception, a prejudice. Gender bias thus describes distortions in perception or biases against women or men on the basis of their gender. In appointment procedures, gender bias can have a positive or negative impact on the evaluation or review of performance. Effective role models and stereotypes, in combination with gender, usually have a subconscious effect on a judgment. Studies on the topic of performance evaluation and gender have shown, for example, that in an experimental set-up representations of female figures were perceived to be smaller than representations of male figures, although all figures in identical surroundings were of the same size. Another study showed that identical curriculum vitae (CV) or resumes were evaluated differently by test subjects depending on whether they were submitted under a male or female name. Significantly more subjects of both genders rated the performance of the men as better and developed the tendency to rather hire the man than the woman, despite identical resumes. (Landeskonferenz der Gleichstellungsbeauftragten, LaKoG, 2011:18ff)
Another mechanism that has a gender-specific effect is so-called homosocial co-optation. Homosocial co-optation refers to the tendency to include primarily those members in an existing network who are considered to be "socially similar." Social similarity can be given or sought in many ways. In addition to characteristics such as social milieu, ethnicity or even scientific community, gender is a relevant criterion. The fact that personnel decisions are influenced by social similarities does not presuppose a strategic decision to specifically exclude women. Rather, the structural dominance of men in organizations combined with the (often subconscious) practice of homosocial co-optation, which is neither limited to organizations nor to men but follows a general pattern of social proximity, leads to the persistence of a male-dominated structure. (Wissenschaftsrat 2007:23ff)