Work out standardised test score conversion instantly with clear inputs, formula shown and shareable results.
Score scaling maps a raw mark onto a fixed reported range so that results are comparable across test forms of differing difficulty. Linear scaling is the simplest mapping; real tests use equating tables that adjust for form difficulty and are not exactly linear.
Linear scaling
Scaled = Minimum + (Maximum - Minimum) x Raw score / Raw maximum
Sensitivity
Scale points per raw mark = (Maximum - Minimum) / Raw maximum
So that the scale has no absolute floor that could be interpreted as a total absence of ability, and to discourage comparison of scaled scores as ratios.
Because the scale range is compressed into relatively few raw marks. On a 60-mark test mapped to 200-800, each raw mark is worth ten scale points.