Fig. 1

Person-item map for the final PCM. The top part displays the distribution of persons’ health levels separately for wave 3 and wave 4. The bottom part shows the item locations (bullets) and item thresholds (circles) for the 12 items. To facilitate the comparison of item thresholds with persons’ abilities, the item thresholds are additionally plotted below the persons’ distributions (of wave 4) by small vertical lines