Hey we've come full circle to PIP again.

But seriously: there isn't a way. This is why sites like Glassdoor are garbage and teacher rating sites have ruined careers over minor issues.

So one email per company is allowed one vote. Similar to how blind allows one account per email. That prevents abuse. You don't like the guy, you can vote once because you have an email address at the company. If 3 or 4 people don't like the guy then the system assumes there is genuinely a problem with him and it reveals itself.

That means one person can't run a smear campaign. At least 2 or 3 other people have to agree with you, and if they do then it's legit. The system masks the persons negative reviews until that manager has accumulated greater than 3 or 4.

Three or four negative reviews from people in the company is NOT a minor issue.