AbstractIntroductionThe Haemophilia Activities List (HAL) and paediatric HAL assess self‐reported limitations in various daily activities. To reduce patient burden, shorter versions of the pedHAL (22 items) and HAL (18 items) have been developed.AimThis study aimed to determine the agreement between the pedHAL/HAL_full and pedHAL/HAL_short and construct validity and internal consistency of the pedHAL_/HAL_short in persons with haemophilia (PWH).MethodsA cross‐sectional secondary analysis of the Hemophilia in the Netherlands‐6 national survey was performed. Adult and paediatric PWH completed the original pedHAL/HAL_full, from which pedHAL_/HAL_short were derived. Score differences between the original and short versions were calculated. Construct validity was studied by testing hypotheses regarding the relationship of the pedHAL/HAL_short with the pedHAL/HAL_full, Haemophilia & Exercise Project Test‐Questionnaire (HEP‐Test‐Q), Canadian Haemophilia Outcomes‐Kids’ Life Assessment Tool (CHO‐KLAT) and RAND 36‐item Health Survey (RAND‐36) (convergent/discriminant validity) as well as its ability to discriminate between subgroups (known‐group validity). Internal consistency was assessed with Cronbach's α.ResultsWe included 113 children (median 10y [range 4–17], 53% severe haemophilia) and 691 adults (median 51y [range 18–88], 35% severe). Scores of the pedHAL/HAL_full and pedHAL/HAL_short were similar with high correlations (>0.9). Construct validity was confirmed for the pedHAL/HAL_short. The HAL_short was able to discriminate between different disease severities and ages. Cronbach's α of the pedHAL/HAL_short was 0.95–0.97.ConclusionThis study confirmed the agreement between the pedHAL/HAL_full and the pedHAL/HAL_short and the construct validity of the pedHAL/HAL_short. The next step is to study construct validity of the pedHAL/HAL_short when administered as short forms.