Chapter 2 Quality assurance

To check for outliers in length measurements, we plotted the distribution of raw length measurements by age and sex against different percentiles of the World Health Organization child growth standard distribution. The majority of observations fell within 3 standard deviations of the mean of the standard for males and females. There were certain cohorts, such as the Keneba cohort, that had a larger proportion of observations outside of 3 standard deviations from the mean. There was a higher variability of length measurements in the PROBIT, ZVITAMBO, and Keneba cohorts.