Two other methods are also used:
- Percentage of the median
The child's weight is expressed as a percentage of the median weight of a child of the same height in the reference data. This measure is simple to calculate, but has the disadvantage that it does not take into account the distribution of the reference population around the median. Because of this, one cannot identify a single cut-off value which can be used across age and height levels, and for all three anthropometric indices.
- Percentiles
A child's weight of a particular height is expressed in relation to percentiles of children of the same height in the reference data.
For example, if 5% of the reference population weigh equal to or less than the child being considered, then the child is in the 5th percentile. The cutoff point for indicating malnutrition is generally taken as <5th (or sometimes <3rd) percentile. Percentiles are directly related to Z-scores, but are not normally distributed - making further analysis more difficult. Moreover in the developing world many children lie below the 1st percentile, which makes a classification based on percentiles useless.
Some authorities consider middle upper arm circumference as a preferable indicator of severe malnutrition, since it is much easier to measure and evaluate in the types of situation where child malnutrition is a problem.