Assessment & Research

An index for assessing weight change in children: weight/height ratios.

Edwards (1978) · Journal of applied behavior analysis 1978
★ The Verdict

Use the Weight Index instead of raw weight to spot obesity treatment gains in growing kids.

✓ Read this if BCBAs running long-term weight programs for school-age children.
✗ Skip if Those working only with stable-height adults or short-term goals.

01Research in Context

01

What this study did

The team looked at two old data sets plus normal growth charts.

They compared plain weight against a new Weight Index.

The index divides weight by height to cancel out normal growth spurts.

02

What they found

The Weight Index caught treatment effects that raw weight missed.

Kids can grow taller without getting thinner, so weight alone hides progress.

The index made long-term change easier to see.

03

How this fits with other research

Ramos-Jiménez et al. (2014) later used the same height-fix idea.

They measured waist and arm circles adjusted for height in teens with ID.

Their index spotted metabolic syndrome early, showing the trick works in new groups.

Nickerson et al. (2015) seems to disagree.

They tested the Body Adiposity Index, also height-adjusted, in adults with Down syndrome.

It failed badly, overestimating body fat.

The difference: the 1978 index uses simple weight/height, while BAI uses a complex hip formula that breaks down in this population.

Same goal, different math, different outcome.

04

Why it matters

If you track weight loss in kids over months, switch to the Weight Index.

It removes the noise of normal growth so you see real change sooner.

One extra division on your calculator gives cleaner data and better parent feedback.

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→ Action — try this Monday

Divide today’s weight by today’s height, plot the ratio, and share the trend with the family.

02At a glance

Intervention
not applicable
Design
other
Population
not specified
Finding
positive

03Original abstract

Weight and height data from two studies were recomputed, and original data were computed using a Weight Index formula that accounts for the interaction of actual weight/height changes in growing children and compares this ratio with that of normed weight/height ratios for equal-aged children. Recomputing the data of one study showed that the Weight Index is a more sensitive procedure for assessing long-term behavioral treatment of obesity for girls than weight alone. Recomputing the data of a second study showed that the Weight Index formula is consistent for boys and girls and is a more sensitive procedure for assessing long-term effects of a variety of medical treatments for obesity than the Ponderal Index or weight alone. Computation of the data for 17 "normal" children in a preschool class showed a zero Weight Index score before and after a six-month interval elapsed without treatment. The procedure may be useful in assessing ponderosity or anorexia over intervals of six months or more with growing children or difference between actual and normed weight over shorter intervals.

Journal of applied behavior analysis, 1978 · doi:10.1901/jaba.1978.11-421