Dear member,
If the HODs have sent the PR forms to you that are duly filled, then it is your duty to maintain proper records of them. You may make a summary sheet and identify who the top performers are, and whose performance is sub-par. The analysis should be helpful in gaining insight into the performance of all the employees.
Nevertheless, your query is also on how, as an HR, to give rating comments. I recommend you refrain from involving yourself in the rating of the employees. HR professionals are the process owners of the PR process. However, the ownership does not give them the right to meddle in the process itself. They cannot expect to have a finger in the PR's pie.
The subordinates work under the nose of the respective HODs. Therefore, they know better who is really smart and who is not. In contrast, HR's association with the employees is remote. In addition to the remoteness, how can HR be an expert in all the departments so as to assess even the performance of the employees? Notwithstanding this, HR may go through the PR forms of all the employees and find out inconsistencies on account of the under-rating of the outstanding employee, if any. The HR professional may also bring to the notice of the HOD a case of misconduct that has not been taken into account while giving excess marks. HR professionals have to seek clarifications from the HODs with due sensitivity, and HODs should not consider it meddling by HR.
Thanks,
Dinesh Divekar