The Authority used two widely accepted economic modeling programs to measure the total economic impacts of its spending from its contracting and construction activities. In September 2017, the Authority issued a retrospective report regarding the total economic impact from its spending activities from fiscal years 2006-07 through 2015-16, which it estimated to be between $3.5 billion and $4.1 billion. In its 2018 business plan, it updated this information to include fiscal year 2016-17, estimating that its economic impact increased an additional $1.6 billion to $1.8 billion during this time.
Although we identified some inconsistencies between the data that the Authority used for its economic modeling and the documentation supporting those data, these inconsistencies were relatively minor. To determine the accuracy of the Authority's data, we randomly selected and reviewed 58 data entries, including expenditure amounts and geographic locations at the zip code level, and we verified the information's accuracy by comparing it to the original invoices or other expenditure data sources. We identified certain inconsistencies: for example, the Authority attributed some expenditures to incorrect counties, which affected the Authority's estimations of jobs in a particular county. In other instances, the Authority explained that due to incomplete expenditure information, it used higher-level financial or past geographical data to make assumptions about the size of expenditures, which could affect the precision of the dollar amounts it reported.
Nonetheless, given the magnitude of the total amounts that the Authority reported and the fact that the amounts are intended to be estimates, we are not concerned that the Authority's economic impact reporting is misleading or substantially under- or overstated. Further, the Authority disclosed the assumptions it made when designing its methodology by discussing those assumptions in the public technical memorandum that accompanied its reports.