Do they know exactly what they are doing wrong?

Be specific, not vague
Use the XYZ formula
In situation X
When you did Y,
It had impact Z
#LeadOthers

I recently completed a communications workshop for an IT team in a large organization. 

I asked them to tell me about a miscommunication.   

One person said:
“Apparently this must happen all the time, but I do not know what it is that I’m mis-communicating since I have not been given examples.  I would like to know so I can analyze why I said what I said and perhaps fix the problem.”

Be specific when giving feedback. One tool to help you be specific is the XYZ formula. 
In situation X
When you did Y
It had impact Z

For example:
John, the other day in the team meeting
When Lisa was talking you folded your arms, rolled your eyes and sighed heavily.
Lisa was offended because she felt disrespected. 
Please don’t do that when others are talking. 

That helps John know exactly what he did and what he should not do. 

Be specific. It matters.