Prevalence of Stunted Children

Impact

% of children aged 6–59 months with a height-for-age z-score < −2 SD from the median of the WHO Child Growth Standards

The indicator measures the prevalence of stunting among children aged 6–59 months in the assessed population. Stunting indicates impaired linear growth and reflects the cumulative influence of nutrition, illness, care practices and wider living conditions before and after birth. For programming purposes, the indicator can help assess the severity of impaired child growth, identify populations requiring attention and track longer-term change where reducing stunting is a plausible programme impact.

Assess the age, sex and length/height of a representative sample of children aged 6–59 months from the population for which the programme wants to estimate stunting prevalence. SMART methodology can be used for this purpose and provides specific guidance when chronic malnutrition is the main survey indicator. Measure recumbent length for children under 24 months and standing height for older children, following standardised anthropometric procedures. Calculate length/height-for-age z-scores using the WHO Child Growth Standards. The numerator is the number of surveyed children with a valid length/height-for-age z-score < −2 SD; the denominator is all surveyed children aged 6–59 months with a valid length/height-for-age z-score.

For programme baseline and endline comparisons, use the same indicator definition, age range, target population and comparable sampling and measurement procedures. The sample size should be sufficient to estimate prevalence with adequate precision and, where detecting programme-level change is an objective, to detect a realistically expected change. SMART provides specific sample-size and survey-comparison guidance (see below). Report prevalence estimates with their confidence intervals and use an appropriate statistical comparison when assessing change between survey rounds; do not interpret differences in point estimates alone as evidence of change. Review anthropometric data quality, including the SMART plausibility checks, before interpreting results, as differences in data quality between survey rounds can affect comparability.

This data can be disaggregated by sex, age group and geographic area. Interpret subgroup estimates only where the sample size provides adequate precision.

1) WHO classifies the public health significance of stunting prevalence as: <2.5% very low; 2.5 to <10% low; 10 to <20% medium; 20 to <30% high; and ≥30% very high. These categories describe population-level public health significance and should not be treated as programme performance targets.

 

2) Use stunting prevalence as a programme impact indicator only when reducing impaired linear growth is a plausible result of the programme’s theory of change and the programme has sufficient duration, population coverage and intensity to influence important determinants of child growth. Do not use stunting prevalence as the sole measure of programme success. Pair it with more proximal indicators that measure the programme’s main causal pathways. A lack of measurable reduction in stunting does not necessarily mean that the programme was ineffective, while a reduction between baseline and endline does not by itself demonstrate that the programme caused the change

    

3) Accurate age assessment is essential because the length/height-for-age z-score depends directly on the child’s age. Use reliable documentation such as birth or health records where available and apply the age-assessment procedures specified in the survey protocol. Where the exact date of birth is unknown, locally adapted events calendars and appropriate caregiver probing can support age estimation (see FAO guidance below).

   

4) Follow relevant Ministry of Health requirements for nutrition assessments, including any requirements for coordination, survey approval and reporting. Use the WHO Child Growth Standards when calculating this indicator. Where a donor or national monitoring framework specifies a particular age range or reporting format, document and apply it consistently across survey rounds.

Also consider using the following indicators:

• Minimum Acceptable Diet (measures a proximal child feeding outcome that many nutrition programmes can influence more directly than stunting)

• Exclusive Breastfeeding Under Six Months (measures an important early-life feeding practice along the pathway to improved child nutrition)

• Prevalence of Diarrhoea Among Children (captures an important illness pathway that can contribute to impaired child growth)

• Prevalence of Global Acute Malnutrition (GAM) Based on WHZ (provides a complementary measure of acute nutritional status, particularly relevant in humanitarian programming)