NYCDOE generated school seniority list question: "Test Score" column

I was at the copy machine today and saw an official copy of the seniority list at my school. It was broken up by job title. There were all different columns that I could figure out. But there was one column I couldn't figure out:

"Test Score"

The scores ranged from 1.0 to 7770.0. What do they mean?

What do the scores indicate?