Measuring Developmental Differences With an Age-of-Attainment Method

Warren O Eaton,Jennifer L Bodnarchuk,Nancy A Mckeen

doi:10.1177/2158244014529775

Warren O Eaton, Jennifer L Bodnarchuk + Show 1 more

Open Access

https://doi.org/10.1177/2158244014529775

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Journal: SAGE Open	Publication Date: Jan 1, 2014
Citations: 8	License type: cc-by

Affiliation: University of Manitoba

Abstract

The sensitive measurement of variation in rate of attainment is an underutilized but useful indicator of individual differences in development. To assess such individuality, we used longitudinal parental diary checklists of infant attainments to estimate the ages at which ubiquitous developmental milestones like sitting and walking were reached. Parents using this diary checklist have been shown to be valid reporters of milestone attainments. Present analyses show that multiple definitions of milestone onset have high reliability as well. Babies differ considerably in their rates of development, and such individual differences in rates may be predicted from other variables with survival (event history) analysis. Ages of attainment for sustained sitting, crawling, and walking were calculated for 519 infants and predicted using 11 common covariates. Our discovery that babies of younger mothers reach these milestones sooner than those of older mothers reveals the value of an age-of-attainment (AOA) approach. A framework with a SAS program for collecting and analyzing AOA data is presented.

Highlights

The timely achievement of motor, physical, language, and cognitive milestones defines healthy development, and the developmentally delayed infant or child may be at risk of various problems (Dosman, Andrews, & Goulden, 2012; Young, 2010)
We identified for use in the survival analysis 11 individual difference variables that are widely used as predictors of infant development
All of them can be found in the scientific literature: age of milestone attainment (Shirley, 1933), prospective diary checklists (Adolph et al, 2002), the SAS Expand procedure (Low et al, 2006), and survival analysis applied to child development data (Singer, Fuller, Keiley, & Wolf, 1998)

Summary

Introduction

The timely achievement of motor, physical, language, and cognitive milestones defines healthy development, and the developmentally delayed infant or child may be at risk of various problems (Dosman, Andrews, & Goulden, 2012; Young, 2010). The typical approach to measuring individual differences in development was pioneered a century ago by Binet and Simon (1916). But variable, outcome measures onto a developmental metric, the individual’s performance was expressed in relation to the average for others of the same age. This became the de facto way to express the developmental status of an individual, as relative to an age-based norm. The group average is treated as the standard of typical development Such an approach has been very useful in many contexts.

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