anchor: Adopting the lag structure used in the Tier 2/Gasoline Sulfur and Heavy-Duty Engine/Diesel Fuel RIAs and endorsed by the SAB (EPA-SAB-COUNCIL-ADV-00-001, 1999), we assume a five-year lag structure.
positive: There is a five-year lag structure in the Tier 2 structure.
negative: Tier 2 uses a ten year lag.