I am working with different enrichment score methods like AUCell and ssGSEA. Now I am trying the seurat function addModuleScore but I am not understanding the method.

For the addModuleScore I couldn't find a good explanation of the method. In the source code they reference "Tirosh 2016, "Dissecting the multicellular ecosystem of metastatic melanoma by single-cell RNA-seq", I went through it but I do not understand it well.

Are the enrichment score I get in AUCell and ssGSEA or the moduleScore I get with the seurat function the same?

Do the average expression levels and the enrichment score means the same?

Thanks in advance