Take a look at this letter from your hiring manager. As you read it, make it personal. Put your name at the top. Think of a hiring manager you think would send you something like this and put his or her name at the bottom. Then send it to a hiring manager who is the least likely person to send it. Hiring top people is a two-way street. Unfortunately, for most recruiters it's always uphill.

Dear (put your name here),

I'm frustrated. You've let me down too many times to let this continue. As your client, I believe your performance must improve in order to succeed in building and developing a strong team. Your role is critical, but somehow you've trivialized it. I don't want to see average candidates anymore and I don't want to see people who are obvious misfits. You need to take on a bigger role in this process, be more involved, and become more of a consultant than a vendor.

However, with that said, I am not without fault here. Since I want you to have an equal stake in the outcome, I must be more involved in the process from beginning to end. With this in mind let's describe our new partnership relationship in finding and hiring more A-level talent.

Here's what I need from you:

1. Learn the job. Understand this above everything else - the job our new employees will do is not what's written on the job description. The job description is a bunch of hogwash that comp or OD needs to meet some self-induced legal need. It does not represent the work a person needs to do to be successful. To get an understanding of what we really do, why don't you meet our best people who do this work already and find out what they really do each day. I'll set up the meetings for you. As part of this, find out why they are better than the people you've been sending me. Before we get started on any assignment I'll review these real job needs with you. This information will help you screen and assess candidates on something meaningful - what the person has accomplished, not how much experience the person has.
2. Understand our industry and the marketplace. I expect you to understand our industry, the big trends, the competition, and the market for the best people in our industry. I also expect you to find great people in complementary industries doing similar work. Do some research on compensation and don't buy into HR-speak and average salary. I don't want to hire average people, so get some comp data on superior people.
3. Teach me how to assess competency. I only interview a few dozen people a year, so I need help here. And forget the behavioral interviewing claptrap. I went to that course three years ago and it doesn't help at all. Every single candidate I meet already knows the questions and the answers since they're all online. I only use these questions when I don't want to hire someone. I heard that Performance-based Hiring provides some great countermeasures, so please check this out.
4. Don't trust my judgment just because I outrank you. I expect you to do your homework. If you believe your candidate is strong, tell me why. And don't back off if I disagree, but defend your position with evidence. Include facts, dates, metrics, real results, and insight. Why not conduct a meaningful reference to validate your assessment. In fact, why not write up your evidence when you send me the resumes.
5. Lead panel interviews and debriefing sessions. The process we use to decide yes or no is too informal. To some degree we combine our assessment of technical competency with a popularity contest to decide. A more formal process using panel interviews would be a great help to get everyone on the same page. You should lead these to keep everyone honest. This way your influence will increase among our team. It seems to me that when people underperform in my department it's more about lack of motivation, poorly prioritizing work, missing deadlines, and an inability to work with people inside and outside the department. To remedy this, why not develop some type of formal debriefing process where we address it.
6. Send me fewer, but better candidates. I'll see every candidate you recommend who you think is worthy, but don't take this responsibility lightly. If you think a person could make the shortlist I'll talk to the person. If someone's on the fence, let's discuss it. All I need to see is three finalists, four at the most. If I need to see more than this, something's wrong. Either we have the specs wrong or our sourcing approach is inappropriate. Let's nip these problems in the bud. It's better for me to spend more time up front, rather than meeting people I shouldn't, and being pressured to hire a mistake in the making.
7. Become an expert in recruiting top performers. The only way we're going to hire more top people is to offer them career moves, not lateral transfers. The big responsibility here is me, and I'm willing to put the effort in if you bring me more A-players. A third of the people in my department have moved on to bigger jobs. Meet them and find out why. Then use this information to convince top people that I want to talk to them. Set up exploratory meetings if you think this will help. I'll go out of my way to meet these people without any expectations whatsoever. I recognize that the best people have multiple opportunities and their ultimate decision will be based on who they work for, the projects they'll be working on, and whether they have the chance to learn more and get ahead more quickly. We have a great story to tell here, and I'm willing to put in the effort telling it, if you bring in the talent.
8. Become a partner with me as we hire great people. I'm willing to go the extra mile here. Hiring top talent is a dual responsibility. You find them and help me close them. I can't do it alone; neither can you. Let's start right now. I've got a few job requisitions I'll be opening over the next few months. The actual specs haven't been worked out, so this is an ideal time to figure out exactly what we want these people to do. By having a few months head start you'll be able to target some new places to look for these people. Since our jobs are in flux, we can even create new jobs to fit the talent you find. We'll just mix and match our current and future reqs to land better people.

That's it on my end, but feel free to modify this plan-of-action in any way you think would help us hire stronger people. I look forward to our new relationship. There is no going back. Hiring top talent is too important to my career and yours, and I'm willing to devote more time than I did in the past to this critical effort.

Regards,

Your Hiring Manager and Partner