In yesterday's post, I once again criticized the belief that "you can't manage what you can't measure." Perhaps the problem is in the word "measure." This assumes that you have more than rough information about something. It says that you know enough to see degrees of variation of that thing. No wonder people think management is a science, if we have such fine measurement capabilities.
This doesn't mean that we should ignore feedback. We should look at everything, and ask questions, and doubt that our first impulse is necessarily the right one. And there are certainly rough tests we can do that give us indicators -- not hard-and-fast rules, but a wavering compass needle that nonetheless helps.
Here's one test that might help, but use it conservatively because once you do it, you'll have a hard time forgetting the results. Look at the members of your team and ask yourself, knowing what you know now, whether you'd still hire them. If the answer for some is "no," ask why they are still there? Most likely is the "sunk cost" model, where "you've already done all the work of hiring them, so to change now would lose all that investment." So you're willing to settle for mediocre because it costs too much to go for great? That doesn't set very well if you think about it that way, does it?