Measure actual private orderflow access of Ethereum block builders

Ascertain the actual private orderflow access of individual Ethereum block builders participating in MEV-Boost auctions—i.e., the extent of exclusive transaction flow from orderflow providers each builder receives—which is not recorded on-chain and not available via relay APIs, to enable accurate calibration and evaluation of builder competitiveness and MEV distribution.

Background

The paper calibrates its simulation model using on-chain and mempool data but notes a bias: on-chain data only reveals the private orderflow included by the winning builder, who likely has superior access. Consequently, observed data cannot reveal the underlying access levels for all builders.

Because private orderflow visibility is limited to what the winner includes on-chain and relay APIs do not expose comprehensive access data, the true private orderflow access for each builder is unobservable. The authors therefore assume access probabilities drawn from a range consistent with on-chain observations. Identifying the true access would improve model calibration and understanding of competitive dynamics.