I can remember three employees who survived a PIP. Two took it as a wake up call and turned into good team members (one turned back into a good team member, the other just got their act together).

The third was a master at reading the PIP, pulling just above the written requirements, then six months later was back in the same stew. Was delighted when they finally accepted a job at our main competitor.

There are others, I just remember three in particular right now. You have to take the PIP seriously: of course it's designed to protect the company, but it should really be the message of last resort rather than a formality.

Also if you have to issue a PIP you need to go back to the manager to see what went wrong. Did you have a hiring mistake or a management mistake or what? Every time I have fired someone I have felt sorry for them (not that I tell them -- they don't want to hear that at that point!). We shouldn't have brought them on, perhaps causing them to quit their previous job or forego another offer, if in the end they didn't work out.

I know some companies assume that if you're on a PIP it's impossible for the emp to recover. If a company is like that I don't see how the PIP would protect them from a lawsuit. It's like H-1B: if you take it seriously it costs you a lot more to hire one than to hire a local. It's again, an action of last resort.