On average, it takes one minute to answer each question and provide comments. If questions are not appropriate given the organization's culture or individual's role, the respondents waste much time. If someone is being rated by twelve people and five questions are not relevant, one hour of time is wasted. Now, consider a project in which 200 people are rated. A custom-designed survey will fit your needs and support the organizational culture and mission.
Confidentiality is important to both the subject and the respondents.
If the subject is not guaranteed that the results will remain confidential, they will tend to feel anxiety about the purpose of the process and the use of the data. If the respondents are not guaranteed that their names will not appear on the report or be linked to specific comments or ratings, then they may not provide accurate responses and be completely open. 360-degree feedback and performance appraisals can complement each other, but should not be linked. If 360 is linked to compensation decisions, it loses its power as a development tool. Further, if people do not get satisfactory ratings, morale can decrease when 360 is linked to performance appraisal mode, but low scores when 360 is used purely for development tend to be viewed as constructive feedback.