For starters, you should know that there could possibly be very insignificant differences in performance levels of the two. (nashvillechatterclass.com)
He would do well to retain such a high performance level in the future games. (anfieldindex.com)
Each of the classroom - observation instruments proposes an incomplete but discrete set of competencies for effective teaching and provides a description of differing performance levels for each competency. (educationnext.org)