For Star CBM Encoding and Encoding Field Test assessments, scores are shown as percent correct rather than Correct Per Minute because Encoding assessments are not timed, and students are meant to finish all items. Benchmarks for Encoding assessments for grades K-3 are based on students' percent correct scores.
There are multiple Encoding forms at each grade level. For grades K-3, to make the results from all forms comparable, and to provide a basis for calculating the norm-referenced scores, Star CBM converts (or equates) the percent correct scores to a common form. Equating eliminates differences in form difficulty so that scores can be interpreted on the same scale. Star CBM does this in steps:
- Star CBM records the number of correct responses on a form (Correct Count).
- The Correct Count score on all of the other forms is equated to the form that has been identified as the easiest form.
- Star CBM converts the equated correct count to a percent correct score. To do this, the equated correct count is divided by the equated number of items attempted. The result is multiplied by 100, then rounded to a whole number.
As a result, percent correct scores indicate the same level of performance across forms, and they can be interpreted regardless of the specific form taken in a measure.
Note: For Encoding Field Test assessments (grades 4-6), percent correct scores are not equated.