The match percentage is calculated based on a distance algorithm. For the STEN scale used in ACE, the distance to 0% is 3 STEN points. This means that a score 3 or more points outside the specified criteria results in a 0% match on the given dimension. All scores within the Criteria range receive a 100% match.
Additionally, the reduction in match percentage from 100% to 0% is not linear: the match percentage drops from 100% to 80% in the first half of the distance to zero, and from 80% to 0% in the second half. Consequently, the closer the score is to the Criteria, the relatively higher the match percentage will be.
The match is also influenced by the priority set on the scale; a score on a high-priority scale will decrease much more if there is a distance between the score and the Criteria, compared to a low-priority scale.