commenting

Star rating with commenting

I am working on developing a 3-5 star configurable rating system to rate the main content within web-based software. The main content can also be commented on, and users can use thumbs up/ thumbs down voting to rate the comments. I was thinking that liking would be better for comments, but am wondering if anyone can point me in the direction of some good usability studies. Non-UX people are requesting that comments should be rated by stars as well, or use five thumbs up instead of stars in the name of consistancy; both feel wrong to me and I need data to prove my point.