To Impute or Not To Impute in Untargeted Metabolomics─That is the Compositional Question.

Summary: Imagine trying to solve a complex jigsaw puzzle where a handful of pieces are missing. In the world of metabolomics—the study of chemical fingerprints in the body—scientists often face this exact problem with their data. To fix it, they usually use mathematical methods to guess, or "impute," the missing numbers. However, this paper raises a red flag: blindly guessing these missing pieces can distort the final picture, leading to false scientific conclusions. The authors suggest that instead of just filling in the blanks, researchers should treat the data as a "composition"—like the relative proportions of ingredients in a recipe—to get a more accurate understanding of biological reality.