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Understanding the TCGA Data Levels
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TCGA Data Levels
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For each *type* of data, there are typically three *levels* of data:
* Level 1 typically represents raw, un-normalized data
* Level 2 typically represents an intermediate level of processing and/or normalization of the data;
* Level 3 typically represents aggregated, normalized, and/or segmented data.

The results of integrative or pan-cancer analyses are sometimes referred to as "Level 4" data.  More information about
`Data Level Classification <https://wiki.nci.nih.gov/display/TCGA/Data+level>`_ can be found on the NCI wiki.