"Population Nutritional Status During Famine"  Michael Golden and Yvonne Grellety, 2002
This work was started to examine the mathematical changes that occur in the distribution of wasting as populations came under stress. It came as a surprise to find that there was no change in the distribution during stress. And that the distribution remained Gaussian. This has major implications. One of which is that the prevalence of wasting can be calculated mathematically from the data, this gives a much more accurate estimate as the actual numerical data collected are used, instead of just whether the individuals are above or below a cut off point.  These calculations are incorporated into ENA software.  As children that have been measured inaccurately tend to be in the tails of the distribution, this can inflate the number  counted below a cut-off point. It may be much more reliable to look at the calculated rather than the counted prevalence, particularly when the numbers are small (ie with SAM).