nutriverse/ipctools

how do we use muac-for-age z-score to determine whether to weight or not the data?

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ernestguevarra commented

I am still not fully understanding this but is this approach being used to avoid having to weight the data, that is, using muac-for-age z-score, cut-offs to determine sam and mam will be used and then use this to calculate prevalence? is this the next step?

tomaszaba commented

I have the same question too. What I know from Dr. Oleg's presentation in Nairobi last year was that muac-for-age z-scores would just be used for data quality checks. But then, last week when I had my first meeting with Douglas (my supervisor) to discuss the checks, he mentioned that prevalence would also be calculated using muac-for-age z-score. I went back to my notes and that was not mentioned. I am not sure if it was a new development after November 2023. I have in my to-do to check with him. I could not do that this week because he is very busy with the analysis situation in Gaza, Palestine. I will share an update on this as soon as I manage to talk with Douglas on this.

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ernestguevarra commented

I think that using muac-for-age for data quality checks is not possible so I think the ultimate goal/plan of CDC/ACF/IPC and all other similar groups is to replace raw MUAC with MUAC-for-age. I have seen surveys recently (and this includes the analysis performed by Vanderbilt on the UNICEF Mozambique data) that is using MUAC-for-age and using the typical -2 and -3 z-scores cut-off.

I have very strong opinions about this but I don't think we need to talk about that. I am just clarifying so we can develop this package appropriately for what you need.

I have re-factored the functions I have in this package to account for no oedema values. Because I developed the functions here modularly, all I had to do was tweak one function and all the checks and prevalence calculation all work accordingly.

tomaszaba commented

Thanks for sharing your perspective around this subject. Have you read Oleg's paper that I shared last week? If not, here is a summary (from his presentation in Nairobi):
MUAC quality.pptx

You can also see more details from his paper here: https://onlinelibrary.wiley.com/doi/full/10.1111/mcn.13478

Anyways, lets see where this goes.