To designate students who qualify for National Merit Scholarship recognition, the National Merit Scholarship Corporation (NMSC) considers the PSAT/NMSQT Selection Index scores of test takers–primarily high school juniors–who meet program entry requirements.
PSAT/NMSQT Selection Index scores differ from PSAT/NMSQT Total scores. Instead of using the 320–1520 scale, Selection Index scores are calculated by doubling the sum of the 8-38 Reading, Writing and Language, and Math Test scores:
(8-38 Reading, + 8-38 Writing and Language + 8-38 Math) x 2 = 48-228 Selection Index
Thus, the Selection Index derives equally from all three Test Scores. Note how this differs from the PSAT Total score, which is 50% math. This inconsistency sometimes results in certain high scorers missing scholarship recognition.