To bring about change in any large company, you need some partner in the high-mid level management who can assist you in bringing about that change. Now this is the problem, if the system is rotten to the core, simply firing the low level solves no problems. You really need to clean the mid level management, and you will never get a true picture of what is going on. All you will see is numbers that will those guys look fabulous.
One of the reasons why Jack Welch got tremendous success with stack ranking was because the managers were subjected to same kind of measurements some one at the bottom was. There fore he was able to clean up a good deal of crap in the management layers.
Unfortunately this is not possible to implement in most companies as either they lack a 'real' leader or the ones implementing, make the process such that they exempted to be judged as a part of it.
Unless, of course, you're near enough to the top of its structure, formal or informal...