[Cochran-Mantel-Haenszel Test: A key tool in medical research for controlling confounding variables].

This article presents a practical application of the Cochran-Mantel-Haenszel (CMH) chi-square test in clinical settings to assess the association between an exposure and an outcome, adjusting for confounding variables through stratification. A case involving 785 schoolchildren was analyzed to determine whether the increase in symptoms among children with Attention Deficit Disorder (ADD) was related to the presence of electronic devices in their bedrooms, considering gender as a potential confounding factor. The CMH test allowed for the control of this effect and improved the precision of the results. Its application not only enables the detection of adjusted associations effectively, but also strengthens methodological rigor and provides a robust statistical tool for research in public health and epidemiology.