HWWAZNCHS (HW8) is a 4-digit numeric variable with 2 implied decimal places.
9997 = Flagged cases
9998 = Missing
9999 = NIU (not in universe)
For surviving children born in the three to five years before the survey, HWWAZNCHS (HW8) reports the difference between the child's weight and the median weight of a reference population of the same age and sex, expressed in units equal to one standard deviation of the reference population's distribution. An anthropometry measure expressed in reference standard deviation units is also known as a Z-score. HWWAZNCHS values are provided in units equal to 100 times the Z-score, to preserve two decimal places without requiring the use of a decimal point. Dividing HWWAZNCHS by 100 will yield a child's weight-for-age Z-score (WAZ) value.
Low child weight-for-age, or "underweight," is a composite indicator of acute and/or chronic malnutrition. The WHO Global Database on Child Growth and Malnutrition considers a weight-for-age Z-score (WAZ) between -2 and -3 to represent moderate malnutrition, and WAZ below -3 to represent severe malnutrition.
Reference populations used to generate HWWAZNCHS draw from 1978 U.S. National Center for Health Statistics (NCHS) international growth reference data. This reference was considered standard by WHO until the 2006 release of the WHO Multicenter Growth Reference Study (MGRS), which generated new standard anthropometry curves using a globally diverse reference population intended to reflect healthy growth conditions.
DHS has also created anthropometric Z-score variables using WHO MGRS 2006 reference populations. HWWAZWHO (HW71) uses WHO MGRS 2006 reference populations to generate weight-for-age Z-scores. This variable was generated for all samples including the necessary anthropometric measurements, including those preceding 2006.