First, let's pretend you're doing UX research. Your team provides you with a report on the surveys that have been completed. But it's not right, it has to be different. What's the right way to say it?
There are three thoughts on this question.
Standards and rules of operation.
If you ask a soccer team to do a UX study, they screw up too. Simply because they don't know how to do it. How would you explain to them the proper research methodology? Let them have a manual, a presentation, or a document. Point by point, they will be able to come up with the right result.
Evidence Base.
If you need to point out team errors, gather specific examples. The general "you're not doing a good job" doesn't work. You need specifics. Having written such a document, you can move on to constructive discussions without emotion.
More respect.
Do you talk about your team with respect? Back to the soccer team. If you wanted to start playing soccer and called your colleagues sucker players, it's unlikely the team would want to play with you. Because you come without respect.
Imagine that your team is doing the best job they can. For you, for a common purpose.
Organize a general meeting and present the new research order. Speak the order and the correctness of the execution.
Now you have quality control.
You have the right not to accept work if its standards are not met.