Please trust me though: I have a good reason for this.
I know full well that people put a lot of stock in rejection letters, especially when the agent has considered the actual manuscript – people are hungry for any tidbit that will give them insight into why something isn’t working or what they can do to improve it. Writers will hunt for hidden meaning, try to divine what the agent was thinking, and attack their manuscript with renewed vigor based on whatever they were saying.
But here’s the thing: I don’t want to lead anyone astray.
If I’m passing on a partial, chances are it’s because I’m just not feeling that zing that I feel whenever I’m reading something I’m going to want to take on. It’s just not for me. But I’m not always able to articulate precisely why exactly that is, and I haven’t read enough to be able to provide a particularly insightful critique.
If I can put my finger on the reason for the lack of zing I will absolutely tell the writer.
If I am just not feeling it and don’t know why: I’d rather be vague rather than say something just to say something. I’d hate for my just-to-say-something reason cause the writer try and revise based on faulty advice.
On full rejections I absolutely give more detail because I’ve read enough to be able to weigh in with something hopefully helpful and tangible. But for partials, I’m really not the best person to be weighing in – I’m not sitting down for an in-depth edit, I’m just reading to figure out whether I’d be the right agent for the project.
The somewhat grim truth is that prospective agents aren’t really the ones who are best equipped to give you good feedback. While I’ll work with authors on revisions if I think the manuscript shows great potential and will give my all to partial critiques for contest winners, an agent’s job isn’t to help everyone who comes their way with thoughtful, helpful critiques. I absolutely do my best, but for the best feedback you’d likely be better off with someone you trust who is reading your work with a thoughtful critique in mind.