Coin Metrics Rebuilds Ethereum Flow Metrics Timing Problem

Coin Metrics has updated Ethereum's historical Standard Flow Metrics, creating a timing issue for tests that use exchange outflows as a trading signal. The crypto data provider recomputed these metrics from Ethereum's first block, using its latest information as part of its Ethereum Point-in-Time release. This update affects all ETH Flow Metrics at daily and hourly frequencies, with corrected history available for backfilling.

The key distinction lies in data vintage, meaning the version of the data used in the test. A chart downloaded today may describe past flows using knowledge acquired later, but a backtest requires the information available when each decision would have occurred. These are different information sets, even when their observations carry the same dates.

Coin Metrics' flow methodology highlights this issue. Standard metrics use all addresses currently known to belong to an exchange or other tracked entity, with each address's history starting at its first nonzero balance. Past values can be restated when additional entity addresses are identified. The Point-in-Time series, however, uses addresses known to belong to the entity during the historical interval, without rewriting earlier intervals with later discoveries.

The underlying problem is attribution. A transfer can be assigned to an exchange retrospectively once the provider identifies the wallet. While this fuller reconstruction may be useful for analyzing past supply movements with today's address coverage, establishing what a trader could have recognized requires the address information and values available at that earlier moment.