Dear Mark,
It is always a good pleasure to read from you.
I have gone through as per the description provided by you and I got the following:
- For the overall GAM prevalence, I used the following details from my dataset:
- GAM by WHZ defined as anything <-2 z-scores
- My mean was of: -0.30
- SD = 1.23.
Please note my test for outliers was excellent (as per the plausibility report I shared before).
With this, the CDF.Normal (-2, -0.30, 1.23) = 0.083468 = 8.35%
For prevalence by sex, I calculated the mean z-score for boys and for girls separately, the SD for each and using the same case-definition of GAM by WHZ. I got the following:
CDF.Normal (-2, -0.30, 1.31) = 0.09719 = 9.72%
CDF.Normal (-2, -0.42, 1.29) = 0.1132 = 11.3%
Overall comments:
I must confess that this was indeed of some use, but at the same time a need to confess that method has the limitation of not taking in consideration bilateral edema. Also, acknowledging the fact that the of of calculated prevalence with a SD of 1 underestimates prevalence, perhaps the SMART methodology team should consider adopting this (CDF) approach and, consequently IPC protocols too as it IPC recommends use of calculated prevalence with SD of 1 when SD is beyond the acceptable ranges.
Million of thanks.