When analysing to examine the malnutrition among children which indicator one should use. For example, some researchers may use the Z-scores directly and some may use the cut off point of -2 Z-score, the divide them into two groups, such as falling below -2 Z-score and above -2 Z-score. When taking the Z-score directly regressions are generally used. When using the indicator generated by the cut off point, researchers use logistic regression. My question is which is analysis is better and why?. Thanks