The D-score: a metric for interpreting the early development of infants and toddlers across global settings
Introduction Early childhood development can be described by an underlying latent construct. Global comparisons of children’s development are hindered by the lack of a validated metric that is comparable across cultures and contexts, especially for children under age 3 years. We constructed and vali...
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2019-12-01
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| Series: | BMJ Global Health |
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| author | Girmay Medhin Charlotte Hanlon Susan P Walker Iris Eekhout Gary L Darmstadt Linda Richter Maureen M Black Ann M Weber Marta Rubio-Codina Stef van Buuren Sally M Grantham-McGregor Maria Caridad Araujo Susan M Chang Lia CH Fernald Jena Derakhshani Hamadani Simone M Karam Betsy Lozoff Lisy Ratsifandrihamanana Orazio Attanasio Bernice M Doove Emanuela Galasso Pamela Jervis Ana M B Menezes Helen Pitchik Sarah Reynolds Norbert Schady |
| author_facet | Girmay Medhin Charlotte Hanlon Susan P Walker Iris Eekhout Gary L Darmstadt Linda Richter Maureen M Black Ann M Weber Marta Rubio-Codina Stef van Buuren Sally M Grantham-McGregor Maria Caridad Araujo Susan M Chang Lia CH Fernald Jena Derakhshani Hamadani Simone M Karam Betsy Lozoff Lisy Ratsifandrihamanana Orazio Attanasio Bernice M Doove Emanuela Galasso Pamela Jervis Ana M B Menezes Helen Pitchik Sarah Reynolds Norbert Schady |
| author_sort | Girmay Medhin |
| collection | DOAJ |
| description | Introduction Early childhood development can be described by an underlying latent construct. Global comparisons of children’s development are hindered by the lack of a validated metric that is comparable across cultures and contexts, especially for children under age 3 years. We constructed and validated a new metric, the Developmental Score (D-score), using existing data from 16 longitudinal studies.Methods Studies had item-level developmental assessment data for children 0–48 months and longitudinal outcomes at ages >4–18 years, including measures of IQ and receptive vocabulary. Existing data from 11 low-income, middle-income and high-income countries were merged for >36 000 children. Item mapping produced 95 ‘equate groups’ of same-skill items across 12 different assessment instruments. A statistical model was built using the Rasch model with item difficulties constrained to be equal in a subset of equate groups, linking instruments to a common scale, the D-score, a continuous metric with interval-scale properties. D-score-for-age z-scores (DAZ) were evaluated for discriminant, concurrent and predictive validity to outcomes in middle childhood to adolescence.Results Concurrent validity of DAZ with original instruments was strong (average r=0.71), with few exceptions. In approximately 70% of data rounds collected across studies, DAZ discriminated between children above/below cut-points for low birth weight (<2500 g) and stunting (−2 SD below median height-for-age). DAZ increased significantly with maternal education in 55% of data rounds. Predictive correlations of DAZ with outcomes obtained 2–16 years later were generally between 0.20 and 0.40. Correlations equalled or exceeded those obtained with original instruments despite using an average of 55% fewer items to estimate the D-score.Conclusion The D-score metric enables quantitative comparisons of early childhood development across ages and sets the stage for creating simple, low-cost, global-use instruments to facilitate valid cross-national comparisons of early childhood development. |
| format | Article |
| id | doaj-art-57d7e4be8ebc45e98cd623fd4bcda651 |
| institution | Kabale University |
| issn | 2059-7908 |
| language | English |
| publishDate | 2019-12-01 |
| publisher | BMJ Publishing Group |
| record_format | Article |
| series | BMJ Global Health |
| spelling | doaj-art-57d7e4be8ebc45e98cd623fd4bcda6512024-12-12T03:10:10ZengBMJ Publishing GroupBMJ Global Health2059-79082019-12-014610.1136/bmjgh-2019-001724The D-score: a metric for interpreting the early development of infants and toddlers across global settingsGirmay Medhin0Charlotte Hanlon1Susan P Walker2Iris Eekhout3Gary L Darmstadt4Linda Richter5Maureen M Black6Ann M Weber7Marta Rubio-Codina8Stef van Buuren9Sally M Grantham-McGregor10Maria Caridad Araujo11Susan M Chang12Lia CH Fernald13Jena Derakhshani Hamadani14Simone M Karam15Betsy Lozoff16Lisy Ratsifandrihamanana17Orazio AttanasioBernice M DooveEmanuela GalassoPamela JervisAna M B MenezesHelen PitchikSarah Reynolds18Norbert SchadyAklilu Lema Institute of Pathobiology, Addis Ababa University, Addis Ababa, EthiopiaCentre for Innovative Drug Development and Therapeutic Trials for Africa (CDT-Africa), College of Health Sciences, Addis Ababa University, Addis Ababa, EthiopiaDepartment of Obstetrics and Gynaecology, Melbourne Medical School, The University of Melbourne, Melbourne, Victoria, AustraliaNetherlands Organization for Applied Scientific Research TNO, Leiden, NetherlandsGlobal Center for Gender Equality, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USADSI-NRF Centre of Excellence in Human Development, University of the Witwatersrand, Johannesburg, South AfricaDepartment of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USASchool of Public Health, University of Nevada, Reno, Nevada, USAInter-American Development Bank, Washington, District of Columbia, USADepartment of Child Health, Netherlands Organization for Applied Scientific Research, Leiden, NetherlandsInstitute of Child Health, University College London, London, UKInter-American Development Bank, Washington, District of Columbia, USA2 Department of Neurosurgery, University of California San Francisco, San Francisco, California, USADivision of Community Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, USAMaternal and Child Health Division, International Centre for Diarrhoeal Disease Research Bangladesh, Dhaka, BangladeshDepartment of Pediatrics, Federal University of Rio Grande, Rio Grande, BrazilCenter for Human Growth and Development, University of Michigan, Ann Arbor, Michigan, USACentre Médico-Educatif Les Orchidées Blanches, Antananarivo, MadagascarNeonatal Unit, John Radcliffe Hospital, Oxford, Oxfordshire, UKIntroduction Early childhood development can be described by an underlying latent construct. Global comparisons of children’s development are hindered by the lack of a validated metric that is comparable across cultures and contexts, especially for children under age 3 years. We constructed and validated a new metric, the Developmental Score (D-score), using existing data from 16 longitudinal studies.Methods Studies had item-level developmental assessment data for children 0–48 months and longitudinal outcomes at ages >4–18 years, including measures of IQ and receptive vocabulary. Existing data from 11 low-income, middle-income and high-income countries were merged for >36 000 children. Item mapping produced 95 ‘equate groups’ of same-skill items across 12 different assessment instruments. A statistical model was built using the Rasch model with item difficulties constrained to be equal in a subset of equate groups, linking instruments to a common scale, the D-score, a continuous metric with interval-scale properties. D-score-for-age z-scores (DAZ) were evaluated for discriminant, concurrent and predictive validity to outcomes in middle childhood to adolescence.Results Concurrent validity of DAZ with original instruments was strong (average r=0.71), with few exceptions. In approximately 70% of data rounds collected across studies, DAZ discriminated between children above/below cut-points for low birth weight (<2500 g) and stunting (−2 SD below median height-for-age). DAZ increased significantly with maternal education in 55% of data rounds. Predictive correlations of DAZ with outcomes obtained 2–16 years later were generally between 0.20 and 0.40. Correlations equalled or exceeded those obtained with original instruments despite using an average of 55% fewer items to estimate the D-score.Conclusion The D-score metric enables quantitative comparisons of early childhood development across ages and sets the stage for creating simple, low-cost, global-use instruments to facilitate valid cross-national comparisons of early childhood development.https://gh.bmj.com/content/4/6/e001724.full |
| spellingShingle | Girmay Medhin Charlotte Hanlon Susan P Walker Iris Eekhout Gary L Darmstadt Linda Richter Maureen M Black Ann M Weber Marta Rubio-Codina Stef van Buuren Sally M Grantham-McGregor Maria Caridad Araujo Susan M Chang Lia CH Fernald Jena Derakhshani Hamadani Simone M Karam Betsy Lozoff Lisy Ratsifandrihamanana Orazio Attanasio Bernice M Doove Emanuela Galasso Pamela Jervis Ana M B Menezes Helen Pitchik Sarah Reynolds Norbert Schady The D-score: a metric for interpreting the early development of infants and toddlers across global settings BMJ Global Health |
| title | The D-score: a metric for interpreting the early development of infants and toddlers across global settings |
| title_full | The D-score: a metric for interpreting the early development of infants and toddlers across global settings |
| title_fullStr | The D-score: a metric for interpreting the early development of infants and toddlers across global settings |
| title_full_unstemmed | The D-score: a metric for interpreting the early development of infants and toddlers across global settings |
| title_short | The D-score: a metric for interpreting the early development of infants and toddlers across global settings |
| title_sort | d score a metric for interpreting the early development of infants and toddlers across global settings |
| url | https://gh.bmj.com/content/4/6/e001724.full |
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