Two years ago I was a research assistant during my undergraduate and my sole duty was the aggregation of many economic surveys, a very tedious task. This data-set, to my knowledge is one of a kind.
Now in graduate school, I had come up with a research idea, and this data-set that I made would be perfect for my research. My research idea is not related to my previous professors, though as of yet, he has no present publication for the research he was doing when I was working for him.
My question is, would it be ethical for me to use this data-set for my own research when I had made it while being employed for my previous professor. The obvious response would be to ask him but sadly we had a falling-out just before I graduated.