Linking Response‐Time Parameters onto a Common Scale

Although response times on test items are recorded on a natural scale, the scale for some of the parameters in the lognormal response‐time model ( van der Linden, 2006 ) is not fixed. As a result, when the model is used to periodically calibrate new items in a testing program, the parameter are not automatically mapped onto a common scale. Several combinations of linking designs and procedures for the lognormal model are examined that do map parameter estimates onto a common scale. For each of the designs, the standard error of linking is derived. The results are illustrated using examples with simulated data.