Dear Anuj,
Interviewees are not your customers so to vie for their feedback. As a follow-up mail, you may send a mail on the quality of the interview. Nevertheless, this option is also fraught with risk.
Suppose you send a detailed questionnaire or a simple mail to get feedback of the job candidate. In turn, if the interviewee gives negative feedback, however, the job candidate was very good. In that case, will it not be embarrassing for the job candidate to join a company or work with a person who had conducted his/her interview? Depending on the number of employees taken on board per month or quarter, you may take the feedback from the newly joined employees on the quality of the recruitment process as a whole.
To improve the quality of the interview, what you need is a video shoot of the interview and then advice from some external consultant on the quality of the questions asked, their sequence, relevance, whether some important question was missed out etc. Occasionally, to probe further, a supporting question or probing question is also very important. This quality feedback will go a long way in improving the interviewing skills of an interviewer.
The job interview is a holistic process. How the candidate was treated before the interview and the quality of the questions asked, both the things are important. The former depends on the culture of your company and the latter on the interviewing skills of the interviewer.
By the way, have you trained your Managers on interviewing skills? Generally, when I conduct the training on "Behavioural Interviewing", I handle all these issues.
Thanks,
Dinesh Divekar
+91-9900155394