Dealing with an employee's fluctuating performance levels

Q: I’ve got an employee whose performance improves for a month or two, but inevitably drops back to an unacceptable level. How do I deal with that?

Seamus: That’s a classic situation that arises, where you crack the whip a little bit with an employee. They perform and whenever the stress of it all eases off a little bit, they’re back to their old routine.

Scott: This question came in from a chap called Mourinho and it’s about another guy called Pogba. It’s an old question.

Seamus: Right. yes. If you’ve got a payoff like Mourinho, you’d be happy enough, wouldn’t you? This is really about keeping on top of the employee. It seems to me there is some sort of performance improvement program