title: Adapting the Bayley Scales of infant and toddler development in Ethiopia: evaluation of reliability and validity.
abstract: There is a need for valid and reliable observational measures of early child development in low-income and middle-income country settings.
  
  
  
  The aims of the study were to adapt the Bayley Scales of Infant Development (Bayley III) for a rural Ethiopian setting and evaluate reliability and validity. The study was carried out between January 2008 and January 2009 in the Butajira demographic surveillance site, south central Ethiopia. The Bayley III was adapted to be socioculturally appropriate for a rural Ethiopian context. Nurses and high school graduates were trained in administration of the measure for 10 days. Inter-rater reliability was evaluated (n = 60). Content, construct and convergent validity was then examined on a population-based cohort of children at the ages of 30 (n = 440) and 42 months (n = 456). Mokken scale analysis was used to determine the scalability of items in unidimensional, hierarchical sub-scales. The mean score was compared by age of child and by stunting status (less than -2 z scores below the standard height-for-age).
  
  
  
  The intra-class correlations between raters were above 0.90 for all sub-scales of the child development measure. Some scale items were not contextually relevant and showed poor scalability. However, the majority of items scaled onto the existing sub-scales of the international measure to form adequate-to-strong hierarchical scales with good internal consistency (Cronbach's α above 0.70 except for gross motor and expressive language sub-scales). Item-scale coefficients were good. The mean score of all sub-scales was significantly higher in the older group of children (33.02 higher total score; P < 0.001) and in the children who were stunted (total Bayley score 2.58 (95% confidence interval 0.07 to 5.10) points lower at 30 months and 3.87 (1.94 to 5.81) points lower at 42 months.
  
  
  
  An adapted version of an international, observational measure of child development was found to be reliable, valid and feasible in a rural Ethiopian setting.
authors.affiliation: Department of Psychiatry, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.|Institute of Psychiatry, Psychology and Neuroscience, Centre for Global Mental Health, King's College London, London, UK.
authors.forename: C
authors.initials: C
authors.lastname: Hanlon
authors.affiliation: Aklilu-Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: G
authors.initials: G
authors.lastname: Medhin
authors.affiliation: Department of Paediatrics and Child Health, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: B
authors.initials: B
authors.lastname: Worku
authors.affiliation: Department of Psychology, Stellenbosch University, Stellenbosch, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Tomlinson
authors.affiliation: Department of Psychiatry, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: A
authors.initials: A
authors.lastname: Alem
authors.affiliation: Health Services and Population Research Department, Institute of Psychiatry, King's College London, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Dewey
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, Centre for Global Mental Health, King's College London, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Prince
mesh_terms: D000367:Age Factors; D002657:Child Development; D003071:Cognition; D003469:Culture; D003906:Developing Countries; D005002:Ethiopia; D005240:Feasibility Studies; D005260:Female; D006130:Growth Disorders / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D007804:Language Development; D008297:Male; D009048:Motor Skills; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D012423:Rural Health / Q000706:statistics & numerical data
keywords: Ethiopia; child development; measurement; sub-Saharan Africa; validation