Should I include PhD experience in MSc application? I have a BSc in computer science and now I'm applying to a Masters program in Human Computer Interaction. A year or so ago I left an unrelated PhD program because I didn't think it would be beneficial to my end career goals. 

Should I include this on my MSc application or leave it out?
You joined a PhD program without a master's degree?

Well... a master of science is about doing an small version of a PhD. In that sense, it could be beneficial to show that you do have some experience in research.

On the other hand, the fact that you left, probably without results or something to prove how well did you do it so far, might not be so positive.

But anyway, honesty should be the most important thing, and you shouldn't hide what you have done before. Also, it is definitely more beneficial to fill those gaps on your CV with the PhD time, instead of letting them think that you were just lounging around...