Dear Deep Mishra,
Once a candidate is selected, he/she is issued the offer letter. The candidate is expected to join the organisation on the date specified in the offer letter. However, if the candidate does not join on the same date or even later, then it is nothing but the "ditching" by him/her. Fairness demands fulfilling the commitment. However, if the candidate does not bind himself/herself to the offer letter, then it speaks of his/her values. Therefore, there is no need to take feedback from such valueless candidates. If you start taking feedback even from the candidates who left you in the lurch, then they may consider it as legitimacy to their rashness. Why do that?
Yes, assessing the sincerity of the job candidate is a huge challenge. Nevertheless, this is where the skillfulness of the interviewer lies. If the candidates are accepting the offer letter and then do not join, then it shows that either their existing organisation negotiated with them for continuing with them or they had a better choice and they availed it of. To avoid this challenge of "now show" by the candidates, your organisation may resort to the following:
a) In the offer letter, you may include a clause for "no show" that says the candidate is required to pay Rs ______ if he/she fails to join. You may consult a lawyer and check whether it will be appropriate to make a legal agreement between your organisation and the candidate.
b) Tell the candidate to deposit the original copies of his/her education certificates after graduation. The certificates will be returned six months after joining. While exercising this option also, get the offer letter drafted by a competent lawyer.
Thanks,
Dinesh Divekar