base off (of) (something else)

1. To derive or found something from some other source or material. A noun or pronoun can be used between "base" and "off." The new play is based off a short story written in 1812. Our research is based off of the work done by our predecessors. I'm pretty sure this movie is based off a book of the same name.

2. To inform or provide the basis for something, as an opinion or conclusion, from something. A noun or pronoun can be used between "base" and "off." I think she's based her low opinion of me off of our first meeting, which unfortunately didn't go well. The decision was based off the recommendations of five different independent experts in the field. Don't just rely on what your parents say—base your opinions off of cold, hard facts.