title: Assessment of data quality in a multi-centre cross-sectional study of participation and quality of life of children with cerebral palsy.
abstract: BACKGROUND
  SPARCLE is a cross-sectional survey in nine European regions, examining the relationship of the environment of children with cerebral palsy to their participation and quality of life. The objective of this report is to assess data quality, in particular heterogeneity between regions, family and item non-response and potential for bias.
  
  
  METHODS
  1,174 children aged 8-12 years were selected from eight population-based registers of children with cerebral palsy; one further centre recruited 75 children from multiple sources. Families were visited by trained researchers who administered psychometric questionnaires. Logistic regression was used to assess factors related to family non-response and self-completion of questionnaires by children.
  
  
  RESULTS
  431/1,174 (37%) families identified from registers did not respond: 146 (12%) were not traced; of the 1,028 traced families, 250 (24%) declined to participate and 35 (3%) were not approached. Families whose disabled children could walk unaided were more likely to decline to participate. 818 children entered the study of which 500 (61%) self-reported their quality of life; children with low IQ, seizures or inability to walk were less likely to self-report. There was substantial heterogeneity between regions in response rates and socio-demographic characteristics of families but not in age or gender of children. Item non-response was 2% for children and ranged from 0.4% to 5% for questionnaires completed by parents.
  
  
  CONCLUSIONS
  While the proportion of untraced families was higher than in similar surveys, the refusal rate was comparable. To reduce bias, all analyses should allow for region, walking ability, age and socio-demographic characteristics. The 75 children in the region without a population based register are unlikely to introduce bias.
authors.affiliation: School of Population and Health Sciences, Newcastle University, 21 Claremont Place, Newcastle, NE2 4AA, UK. heather.dickinson@ncl.ac.uk <heather.dickinson@ncl.ac.uk>
authors.forename: Heather
authors.initials: H
authors.lastname: Dickinson
authors.forename: Kathryn
authors.initials: K
authors.lastname: Parkinson
authors.forename: Vicki
authors.initials: V
authors.lastname: McManus
authors.forename: Catherine
authors.initials: C
authors.lastname: Arnaud
authors.forename: Eva
authors.initials: E
authors.lastname: Beckung
authors.forename: Jérôme
authors.initials: J
authors.lastname: Fauconnier
authors.forename: Susan I
authors.initials: SI
authors.lastname: Michelsen
authors.forename: Jackie
authors.initials: J
authors.lastname: Parkes
authors.forename: Giorgio
authors.initials: G
authors.lastname: Schirripa
authors.forename: Ute
authors.initials: U
authors.lastname: Thyen
authors.forename: Allan
authors.initials: A
authors.lastname: Colver
mesh_terms: D015982:Bias; D002547:Cerebral Palsy / Q000503:physiopathology / Q000523:psychology*; D002648:Child; D003430:Cross-Sectional Studies; D019988:Children with Disabilities / Q000523:psychology*; D005060:Europe; D005190:Family / Q000523:psychology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D011594:Psychometrics; D011788:Quality of Life; D012042:Registries; D012107:Research Design; D018434:Sickness Impact Profile; D012931:Social Environment; D012944:Social Support; D011795:Surveys and Questionnaires; D016138:Walking / Q000502:physiology