Characterising copy number alterations

Hi,

I have been using the Cell Model Passports Copy number alteration “CNV Driver gene data” (https://cog.sanger.ac.uk/cmp/download/cnv_summary_20220509.zip) dataset.

I am a bit confused and would like clarification with how the CNV scores are calculated (https://depmap.sanger.ac.uk/documentation/datasets/copy-number/) as some of the values are 2 or 3 but it has been characterised as a “loss” when the ranking system says 2 = neutral and 3 = gain.

Thanks in advance for any help