Stocks are categorized in four levels, by sector, sub-sector, industry, and sub-industry. We can rank stocks relatively; vs. its industry or sector. It's a powerful tool because sometimes the factor only works well relative to industry. But sometimes it may be better to compare a stock to its peers in the same sub-industry or sub-sector.

For example, the SOFTWARE industry contains a few sub-industries such as "games" and "home & office". Can you think of scenarios where you'd want to compare game software stocks to other game software stocks (the same sub-industry) and not "home and office" (the same industry)? There are many many such examples.

Let's have the option of comparing a stock to its sub-industry and sub-sector comps.