I have a dataset comparing approach 1 vs approach 2 for an measurement, the total events rate in both groups are 32% vs 27% (kindly of similar), but given the data are nested under each approach, I sued multi-level logistic regression to calculate the OR, see the OR in the below figure

however, the OR from multi-level fixed model is much higher than the standard OR using 2X2 table (OR: 2.9 vs 1.2).

I am trying to explain the rationale behind it.

Appreciate it if anyone who can provide some clues


thanks



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