Questions about normalization method CLR vs TSS

Adding to Himel’s points:

  • TSS is a normalization technique, and CLR is normalization + transformation.
  • Normalization removes per-sample technical effects (e.g. library size), and transformation make skewed data nicer so the model fits are valid.
  • You should always do both. MaAsLin 2 default is LOG transformation + TSS normalization.
  • In practice, CLR(data) = CLR(TSS(data)) ~ LOG(TSS(data)). So most often you should see similar results by using CLR, vs. by using the MaAsLin2 default.
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