Look, I know everyone (except me) hates performance improvement plans. Unfortunately, a recent survey by HR Acuity finds they are on the rise.
Managers perceive them as busy work — something they have to do just so they can fire someone. Employees feel that being put on a PIP is akin to being told they have 90 days left to live. And HR is often left frustrated with the results: as HR executive Anna Tavis recently told The Wall Street Journal, “I spent 15 good years on Wall Street and other places. It’s a cover up. It's window dressing. None of these performance improvement plans lead to improving performance."
If you're writing a PIP with the goal (stated or unstated) of terminating the employee, and the PIP is just a way to get to that point, then it makes perfect sense that they won't improve. The manager isn't offering the right support and the employee doesn't try, because the employee knows they'll fail.
Please select this link to read the complete article from Inc.