Child growth standards

To facilitate re-running of nutritional survey data based on standardized approach, WHO has developed an online tool to analyse child anthropometric data. The WHO Anthro Survey Analyser aims to promote best practices on data collection, analyses and reporting of anthropometric indicators. It offers analysis for four indicators: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age.

The methodology was updated considering the complex sample design of most of the recent surveys, compared to the methodology used in Anthro software (below). Improvements affect only measures of accuracy around estimates (i.e. standard errors and confidence intervals). The tool is based on R, with Shiny package.

Outputs include a set of z-scores, a file with prevalence estimates by the various stratification variables following the format in the expanded database, a report template on data quality assessments and a summary report with a template to be filled in with basic required survey information and ready-to-use graphics and tables depicting survey analysis results.

The tool online and offline versions can be accessed from the links below. Users are encouraged to read the quick guide carefully before using it.

The software is design for Windows and consists of three modules: i) Anthropometric calculator, ii) Individual assessment, and iii) Nutritional survey. The first two modules concern the calculation of z-scores (or percentiles) for the assessment of individual child’s growth, and thus very pertinent for clinical application. It should be noted however that, for the module “Nutritional survey”, the methodology for calculating the estimates of prevalence and confidence intervals was still not updated to align with the more recent tool above, the WHO Anthro Survey Analyser.

The main differences between the old standard analysis and the most recent one, are:

• Prevalence estimates in Anthro Software include children up to 60.99 months, while in the Anthro Survey Analyser, only children below 60 months are included, to align with the target indicator age group (under 5 years).
• Calculation of confidence intervals around prevalence estimates was not updated in Anthro Software to take into consideration complex sample designs.
• Anthro Survey analyser included a new data validation related to the information on measurement position (recumbent length or standing height).

Language options enable users to change from the default English to Chinese, French, Spanish, Russian or Portuguese.

Before downloading the software please read the license agreement.

• Open license agreement
  pdf, 9kb

To download the software and respective manuals click on the links below. We recommend users to study first the manual, in particular the description of the requirements and installation (e.g.,.NET framework required before installing the software).

The R package “anthro”

It includes functions to calculate z-scores and prevalence estimates (and CIs), and z-score summary statistics (and CIs) based on methodology recommended and described in the guide document jointly released by WHO and UNICEF Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old. It provides results for the indicators: length/height-for-age, weight-for-age, weight-for-length, weight-for-height, body mass index-for-age, head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age. The package is available in the CRAN repository at https://CRAN.R-project.org/package=anthro.

STATA macro

UNICEF has updated the STATA macro for analysing survey anthropometric data for children under five years of age based on the methodology recommended and described in the guide document jointly released by WHO and UNICEF Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old, aligned with the R package. It offers analysis for three indicators: length/height-for-age, weight-for-age, weight-for-length and weight-for-height. The macro is available at https://github.com/unicef-drp/igrowup_update or upon request via email data@unicef.org. Should you have any issue with this STATA macro, you should contact the UNICEF Data & Analytics Division for support.

Other macros

Macros in SAS or SPSS exist but are not completely aligned with the latest methodology for the calculation of the prevalence estimates and confidence intervals. They can still be used for the calculation of z-scores and prevalence estimates (not confidence intervals). These macros will be updated in the near future.

Should you encounter problems with the download due to slow internet connection, please send your contact details to the address below and we shall mail you a CD ROM including the software and manuals.

To report any software or macro problems please make a brief bug report containing the details on issue (product, kind of problem found, whether it appeared systematically or randomly, computer system, etc.). Send this brief report including the error log file to the following email address: who_anthro@who.int with the informative subject. Please note: This is not a helpline address.