Idaho’s 2017 ACT scores exceeded the national averages — but only a relatively small fraction of Idaho students took the college-placement test.

The average ACT composite score for Idaho students came in at 22.3, compared to a national average of 21.0. Idaho students topped national averages on all four phases of the test: English, reading, math and science.

However, Idaho scores dropped across the board from 2016. And there is another key caveat. Only 38 percent of Idaho’s high school class of 2017 took the ACT, compared to 60 percent of students nationally.

Idaho students are required to take a college placement exam, but the state makes the SAT available to students for free. As a result, 89 percent of Idaho high school juniors took part in the most recent free “SAT Day” in April.

That’s why Idaho’s ACT takers tend to be a small, self-selecting sample. According to an ACT report issued Thursday, 87 percent of Idaho ACT takers plan to attend college. Overall Idaho college attendance rates hover around the 50 percent mark.