Reported volume vs measured volume — I compared 43 exchanges and the gap is bigger than I expected

Every "24h volume" you read on the big trackers is a number the exchange reported about itself. I've been computing it the other way — walking order books and reading on-chain swaps — and for some venues the difference is an order of magnitude.

The most useful signal isn't the volume itself, it's volume vs depth: a venue showing $500M/day with only $200k of depth within ±2% of mid is not a place you can actually exit a position. Curious what people here use to judge whether a venue's liquidity is real, beyond trust scores.