How do discrimination decisions by the project manager affect the project success?

Discrimination means unfair. If the employees who are working in the same project felt that, make sure indeed that would be the bad end of any project. The most important and major subject in project manager skills is to be fair and treat all as same. Sure there are some employees doing faults during the work and some others are doing well. We agree, the mean job of the project manager is to instruct all of them. To avoid any discrimination, he should make single face to face meeting after work with employees who did faults and discuss that matter with them without and embarrassment in front of others.

Discrimination can be either positive or negative, meaning that the first determines leading by example and the latter is biased to say the least. Discrimination can turnout to be negative as well if the one in charge doesn't rotate the personnel, thus creating bias. Discrimination is perhaps one of the most important aspects of management, because it tends to mitigate the risks, but it should also be used according to a social model of development or applied with social responsibility towards integration.

The question is far more important than my answer.

They destroy the team's moral leading to break in communication and ultimately failure to meet project goals.