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Data Quality and Verification

Data Quality and Verification. Office of Highway Policy Information Federal Highway Administration. Why Verify. Verification versus Reviews MF reviews look at process Verification looks at specific numbers Old system is hand-entry of the data Nobody’s perfect

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Data Quality and Verification

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  1. Data Quality and Verification Office of Highway Policy Information Federal Highway Administration

  2. Why Verify • Verification versus Reviews • MF reviews look at process • Verification looks at specific numbers • Old system is hand-entry of the data • Nobody’s perfect • Motor Fuels team checks and re-checks • Errors still possible

  3. Correspondence • Verification memo • Dated: • Response due April 15 • Virtually assured data will change • Second round • If no changes in the first round – FYI • If changes in the first round – re-check

  4. How to evaluate • Compare State 551M monthly to the MF-33GA (gas and gasohol) and the MF-33SF (diesel and other special fuels) • Sum all the months in the year and check against the MF-21 • Gasoline Total Consumption column • Special Fuel Private and Commercial Highway Use column • Note – there are reasons these don’t always match

  5. Table MF-21- Motor Fuel Use • Summary of the FHWA annual analysis • Draft attribution data • Available for review and correction • Becomes the MF-27 (finalized) • As MF-27, used to attribute federal highway revenue to the States

  6. MF-21: A Closer Look - I • Starting point: two-thirds over from the left • Special fuels column • Data taken from State data • Removed all non-highway gallons • That’s it for special fuels • Gasoline • Remember: gasoline/gasohol combined • Start at column Total Consumption: agrees with total on MF-33GA

  7. MF-21: A Closer Look - II • Next column to the left: Losses • Depends on State legislation • None • Flat percent losses • Actual losses • Complicated combinations • Limited to one percent of total consumption plus actual losses • New procedures in place

  8. MF-21: A Closer Look - III • Non-highway Use • Two non-highway types • Private and Commercial • Public • Two treatments • P&C either State or model data • Public is all model results • Breakdown by P&C type in Table MF-24

  9. MF-21: A Closer Look - IV • Public on-highway use • Two types • Federal civilian use • State, County, Municipal, and Native American government use • All data generated from FHWA models Note: Total Highway Use column is combined gasoline\gasohol used in attribution

  10. Summary • Verification: • Is different than Process Review • Final State data for attribution • Should not substitute for checking the data • Month-by-month • With future techniques

  11. Modeling Data • Why FHWA models data • Consistency among States • Data not otherwise available • Model off-highway gasoline • P&C gasoline off-highway • Public gasoline off-highway • Relatively small impact

  12. Modeling Data • Gasohol Model • Relatively large impact • Why an issue • Federal/State definition differences • States don’t report by federal definition • Attribution impact • Federal revenue • Incentives

  13. Modeling Gasohol • How the current model works • IRS reports total gasohol revenue • States providing reasonably good gasohol data are allocated their share of gallons derived from IRS data • States with no gasohol are allocated zero gallons of gasohol • States not in either of these categories are allocated the remaining gallons derived from

  14. Modeling Gasohol • Regression analysis • Dependent variable: number of ethanol gallons consumed • Independent variables: • Ethanol plant proximity • Producer’s incentive amount • VMT in State non-attainment areas proportionate to State VMT • Blender’s incentive amount • Total gasoline consumed in the State

  15. Modeling Gasohol Sum the estimated amounts derived from the regression calculation • Derive each estimated amount’s percentage of the total estimated • Multiply these percentages by the IRS remaining control total • Derive the distribution for each State’s three levels of gasohol

  16. Modeling Gasohol • Model issues • Over emphasizes proximity to gasohol production • Conversion from MTBE to ethanol will spread gasohol use • Model needs improvements

  17. Modeling Gasohol Summary • Significant impacts • State data necessary but not sufficient • Needs improvements before re-authorization

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