I recently have started to look at some data from CRSP, and they have a metric called Value Weighted Return (two versions with and without distributions).
When I looked it up, it seemed that this metric was not used anywhere else, and the explanation on the site did not help (quoted below):
VWRETD indices contain either the daily or monthly returns, including all distributions, on a value-weighted market portfolio (excluding American Depository Receipts (ADRs)).
How is this useful? What is the portfolio? If we don't know the portfolio, what makes this number meaningful?