How to read the labeled enron dataset categories? I am trying to use the labeled Enron dataset (link) but I am really confused about the labeling system they use. I understand the Cat_[1-12]_level_weight is some form of confidence level. This dataset labeled by multiple students. Cat_[1-12]_level_weight increases with the number of the same label assigned by multiple students to a certain row (sample). But, what is for instance the Cat_1_level_2? From the overview (in the link), I guess Cat_1 mean &quot;Course genre&quot; and level_2 mean  &quot;Purely Personal (49 cnt.)&quot; ? If so, why the Cat_1_level_2 has values like 1, 2, 3, 4, etc.? I am really confused.
Looking at the first link from your post there is an in-depth overview of the different categories. Cat_#_level_1 denotes the top level category (12 in total) whereas Cat_#_level_2 denotes the second level category (up to 19 categories, depending on the level 1 category). E.g. an email with the labels Cat_3_level_1 and Cat_6_level_2 has the label california energy crisis / california politics (category 3.6). You therefore need to combine the two levels to get to the label that belongs to the second level category.