I am new to this database. I could not find instructions on how to interpret the values posted in the .csv files in downloads in each cell – the minus and the positive ones, what do they signify. For example, I downloaded the genetic dependency datasheet for RNAi combined so what to the values in the cells mean?
Probably the best places to start are the README file which explains the contents all of the files that you can download in a DepMap data release.
However the values you’re looking at are what we call “gene effects” of knock-out or knock-down. The most concise explanation for gene effect can be seen at the bottom of the Dependent Cell Lines tile on the gene page: