PMC

Item map for activity scale. The item categories are represented by the activity summary score that produces the expected value in the middle of each category range. The expected value is defined by the sum of the category values multiplied by their probabilities.

Discriminant validity of the activity scale with the Manual Activity Classification System. Bar graphs depict average score (95% confidence interval) at different manual severity levels with different Computerized Adaptive Test item stop rules in comparison with the full item bank.

Item Characteristics and Differential Item Functioning (DIF)
^aLogit scale.
^bLikelihood ratio chi-square test P value for each item.
^cCorrelation between the item and the person score.
^dDIF definitions: 1=DIF across ages, 2=DIF across sexes, 3=DIF across Manual Ability Classification System groups, 4=DIF across Gross Motor Function Classification System groups, 5=DIF across cerebral palsy types (quadriplegic, diplegic, hemiplegic).

Discriminant validity of the activity scale with the Gross Motor Function Classification System. Bar graphs depict average score (95% confidence interval) at different gross motor severity levels with different Computerized Adaptive Test item stop rules in comparison with the full item bank.