How do you survive PIP? Can anyone who's gotten off PIP give some advice as to what I should be doing? Should I just screw the job and start looking for other positions ASAP? Do you have to tell your prospective employer that you were placed on PIP?
Never tell your prospective employer that you were placed on PIP. Interview and leave.
Think of PIP as a notice period that the employer gave you. Invest as much time applying and studying for the interview process as possible! Use your holidays if needed for interviews and get out before they do it for you!
PIP is only to reduce resource count. Start looking for a job. Note that it's not because you were not skilled or smart, just that they had to let go off some people and had to make some hard decision.
Agreed with other posters that there is no making it off PIP. Try to take as many positives as you can away from the experience. Learn from your mistakes and make sure to get your resume up to date with all of the projects you worked on. Begin heavy networking immediately!
I had seen some folks going on PIP both in public and in private industries but not once have I seen someone survive it and came out as a "stronger employee" at the same company. They all either voluntarily left within a few weeks or were eventually let go after a few months. I don't think you need to broadcast to the world that you were placed on one but yeah, it would be the time to look around and send in applications right away.
Always be looking. Doubly so on PIP.