Having worn a interviewing & selecting hat for <corporation>, I can say my objectives for rejection communication were:
(1) conveying the fact of it politely and unequivocally,
(2) ensuring that the process halts immediately, and
(3) leaving an impression such that the candidate's likelihood of thinking & speaking ill of us in future is minimised.
The fact is, rejection usually amounts to disappointment and in some people that means they're about to pass through the stages of grief, often quite quickly. As the rejector you have a chance of being on the receiving end of the anger & bargaining stages from a rejectee.
This creates an incentive to give away as little as possible. If one states that the candidate was weak in a specific area, there are a few - just a few but it's enough to be a major deterrent - that will treat this as an invitation to negotiation over that and/or related points. In the worst case this led to a large volume of unsolicited communication that proved challenging to curtail.
Thus goals (1) and (2) had not been achieved and goal (3) was abandoned in the interests of time.
From another dimension, IANAL but I have also been advised by Ms.IAAL that being specific also opens the door to a risk of being wrong (or even being simply perceived to be wrong), and thus a liability concern.
Although many of us would like to get that feedback, there are reasons not to give specific feedback to job candidates: it prevents you from making any statements that could be held against you (esp. legally); it doesn't take time away from other more valuable work; it discourages people from attempting to hone their interview skills to cover for weak fundamentals; it saves you an awkward moment if the no-go decision was based on personality more than technical chops.
If you really want that kind of feedback, do some mock interviews. What you're asking for just isn't a service that prospective employers have much incentive to offer.
(1) conveying the fact of it politely and unequivocally, (2) ensuring that the process halts immediately, and (3) leaving an impression such that the candidate's likelihood of thinking & speaking ill of us in future is minimised.
The fact is, rejection usually amounts to disappointment and in some people that means they're about to pass through the stages of grief, often quite quickly. As the rejector you have a chance of being on the receiving end of the anger & bargaining stages from a rejectee.
This creates an incentive to give away as little as possible. If one states that the candidate was weak in a specific area, there are a few - just a few but it's enough to be a major deterrent - that will treat this as an invitation to negotiation over that and/or related points. In the worst case this led to a large volume of unsolicited communication that proved challenging to curtail.
Thus goals (1) and (2) had not been achieved and goal (3) was abandoned in the interests of time.
From another dimension, IANAL but I have also been advised by Ms.IAAL that being specific also opens the door to a risk of being wrong (or even being simply perceived to be wrong), and thus a liability concern.