Objective: to validate a simple instrument for the measurement of parent-reported health and morbidity in infancy and childhood suitable for research and service planning purposes and capable of measuring both cross-sectional and longitudinal health and morbidity experience in a child population.
Setting: child health clinic (CHC), child development unit (CDU) and paediatric outpatient department (OPD) in Coventry.
Design: 3-phase field testing to establish test-retest reliability, validity and inter-observer variation of the instrument. Field testing samples: phases 1 and 2; 188 parents of pre-school children attending one of the three health service settings-CHC, CDU or paediatric OPD; phase 3; 40 parents of pre-school children attending CHCs.
Methods: test-retest reliability of each domain of the WCHMP was estimated using weighted Kappa; criterion validity was estimated for selected domains against health records; construct validity against medically plausible constructs was tested by comparing responses between domains; Inter-observer variation was estimated using weighted Kappa.
Results: the test-retest reliability of the WCHMP varied from 'moderate' for behaviour, functional health and life quality status to 'very good' for acute significant illness and hospital admission status; criterion and construct validity were high; weighted Kappas for all domains for inter-observer variation between the researcher and family health visitor were in the 'good' to 'very good' range and inter-observer variation remained unaffected by change in the order of administration of the WCHMP.
Conclusions: the WCHMP is a simple measure of parent-reported health and illness which, on field-testing, has been shown to be reliable and valid with low inter-observer variation. After further development and validation including incorporation into the parent-held record, it should be suitable for use in infancy and early childhood to collect cross-sectional and longitudinal health and morbidity data for research and service planning purposes.