While some hiring managers will occasionally help candidates out by giving them feedback about where their candidacy could have been stronger, the majority of employers don't tell candidates why they were rejected. Many employers even have policies prohibiting giving feedback.
Here are the six most common reasons why.
1. They don't have time. Hiring managers are busy, and they're not job coaches. Providing thoughtful feedback takes time, and it's not what they were hired to do. Some will give advice anyway—but it's a favor when they do it, not an obligation.
2. Too many candidates will argue or debate if they get feedback. Ask any hiring manager who has taken the time to give a candidate feedback, and you'll hear stories of defensive and even angry reactions. Since providing feedback is a favor, many interviewers conclude that they'd just rather not deal with this.
3. Their lawyers won't let them. Many interviewers are under orders from company lawyers not to get into the reasons for job rejections, in case a candidate doesn't like the explanation and decides the "real" reason must be discriminatory. Plus, if they tell you they're looking for more experience in X, but they ultimately hire someone without that experience (because she comes highly recommended by a trusted client, or because she just blew them away in the interview, or any of the many reasons that could happen), you might feel deceived. They don't want to deal with that.
4. The answer has nothing to do with you. It's often about another candidate—the person who got the job simply dazzled everyone in her interview, or had amazing experience with widget making, which wasn't mentioned in the job description but happens to be an area the company is expanding into next year. Or they just liked her better. These are very common reasons for hiring decisions, but they don't make for helpful feedback to you.
5. They're not comfortable sharing awkward or personal criticisms with you. For instance: You chronically interrupt, you seemed vaguely angry, you looked unkempt, you seemed high maintenance, you didn't seem smart enough, or you creeped out the receptionist. These aren't uncommon reasons for rejecting someone, but most employers aren't going to have these awkward conversations with people who aren't working for them.
6. They did tell you the reason, and you don't believe it. Much of the time, it's really true that you were impressive but someone else was simply the better fit. There's not always a reason beyond that.
Alison Green writes the popular Ask a Manager blog, where she dispenses advice on career, job search, and management issues. She's also the co-author of Managing to Change the World: The Nonprofit Manager's Guide to Getting Results, and former chief of staff of a successful nonprofit organization, where she oversaw day-to-day staff management, hiring, firing, and employee development.