Suppose Intervention A and Intervention B are randomly allocated to 50 participants each (n = 100) to compare their efficacy in preventing a condition after a certain time period. Efficacy is ordinally categorized into six: no condition (full prevention), I – mild condition, II – moderate condition, III – severe condition, IV – critical condition, V – death. The following table is generated (see image attached). For the sake of discussion, let’s assume that this ordinal categorization is proper and evidence-based.

What statistical method/tool should I use if I wish to compare the distributions of the two groups across the ordinal categories? Because of the ordinal nature of the variable, I think that Chi-square test or the Fisher exact test (the latter I have yet to see being done outside of a 2 x 2 contingency table) cannot be used in this case. Is either Cochran-Armitage test for trend or Cochran–Mantel–Haenszel statistics viable here? Thank you!

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