4.3 Accretion rates
4.3.1 Description of the model
For each of the three airports, direct, multiplier, and total impacts were estimated in terms of employment, payroll, and output for airport operations and on-airport activities; off-airport aviation-related businesses (Philadelphia International and Pittsburgh International Airports only); and commercial service and general aviation visitors traveling to/within Pennsylvania. The discussion below details the process used to update the economic impacts for each airport.
Philadelphia International Airport
There were notable differences between the 2005 economic impact study for Philadelphia International Airport and this PennDOT Bureau of Aviation economic impact study in terms of how airport impacts were estimated. Various assumptions and modifications to the 2005 study’s
methodology are required so that the economic impacts of Philadelphia International are presented in a manner consistent with this study’s methodology.
Direct On-Airport Impacts – Direct employment impacts from the 2005 study remain unchanged. To update direct payroll impacts associated with airport tenants, estimates of payroll for each tenant category in the 2005 study are identified using ratios of payroll per employee. These ratios are derived from the consultant’s in-house database
compiled from airport economic impact studies conducted throughout the United States.
The direct output impacts from the 2005 study are inflated to 2010 dollar values using the Bureau of Labor Statistics’ (BLS) Consumer Price Index (CPI).
Capital Improvement Projects (CIP) expenditure data for 2008-2010, obtained from City of Philadelphia online reports, is used to estimate additional direct employment, payroll, and output impacts generated by on-airport construction projects. Employment and payroll impacts associated with CIP expenditures are identified using Pennsylvania-specific employment ratios per $1 million of CIP output from the IMPLAN model and the BLS average state wage for construction-related workers in Pennsylvania ($35,100).
Direct Visitor Impacts – Commercial service and general aviation visitor expenditures are identified using the same methodologies in the PennDOT study. For commercial service visitors, calendar year 2010 passenger enplanements and 2009-2010 visitor
percentages are used to estimate annual visitor impacts. Data regarding average visitor spending is based on the consultant’s in-house database of visitor spending at
commercial service airports throughout the United States and Pennsylvania. For general aviation visitors, the number of annual true transient arrivals based on aircraft operations data from the airport’s FAA 5010 Form is used to estimate annual visitors. Data
regarding average visitor spending is based on the process used to categorize airports by general aviation visitor expenditures explained earlier in this report. Employment and payroll impacts associated with commercial service and general aviation visitor
expenditures are identified using Pennsylvania-specific employment ratios per $1 million of visitor output from the IMPLAN model and the BLS average state wage for workers in Pennsylvania in service sectors ($21,600).
Off-Airport Impacts – The employment impacts (not including multiplier impacts) for freight forwarders, ground couriers, the United States Postal Service, and warehousing businesses from the 2005 study remain unchanged. To update payroll impacts (not including multiplier impacts) associated with these businesses, estimates of payroll for each business category are identified using ratios of payroll per employee. These ratios are derived from the consultant’s in-house database compiled from airport economic impact studies conducted throughout the United States. The output impacts (not including multiplier impacts) from the 2005 study are inflated to 2010 dollars using the BLS’ CPI.
Multiplier Impacts – Pennsylvania-specific IMPLAN multipliers are applied to the direct on-airport, direct visitor, and off-airport impacts to estimate multiplier impacts.
Total Impacts – Total impacts are estimated by summing the direct on-airport, direct visitor, off-airport, and multiplier impacts.
Pittsburgh International Airport
Direct On-Airport Impacts – Direct employment impacts from the 2007 study remain unchanged. The direct payroll and output impacts for airport tenants from the 2007 study are inflated to 2010 dollars using BLS’ CPI.
CIP expenditure data for 2008-2010 provided by the Allegheny County Airport Authority (ACAA) was used to estimate additional direct employment, payroll, and output impacts generated by on-airport construction projects. Employment and payroll impacts
associated with CIP expenditures are identified using Pennsylvania-specific employment ratios per $1 million of CIP output from the IMPLAN model and the BLS average state wage for construction-related workers in Pennsylvania.
Direct Visitor Impacts – Commercial service and general aviation visitor expenditures are identified using similar methodologies detailed for these aviation impacts in this study.
For commercial service visitors, calendar year 2010 passenger enplanements and 2009-2010 visitor percentages are used to estimate annual visitors. Data regarding average visitor spending from the 2007 study is inflated to 2010 dollars using BLS’ CPI. For general aviation visitors, the number of annual true transient arrivals based on aircraft operations data from the ACAA is used to estimate annual visitors. Data regarding average visitor spending from the 2007 study is inflated to 2010 dollars using BLS’ CPI.
Employment and payroll impacts associated with commercial service and general aviation visitor expenditures were identified using Pennsylvania-specific employment ratios per $1 million of visitor output from the IMPLAN model and the BLS average state wage for workers in Pennsylvania in service sectors.
Off-Airport Impacts – The employment impacts (not including multiplier impacts) for off-airport businesses such as off-airport parking providers from the 2007 study remain unchanged. The payroll and output impacts (not including multiplier impacts) for these businesses are inflated to 2010 dollars using BLS’ CPI.
Multiplier Impacts – Pennsylvania-specific IMPLAN multipliers are applied to the direct on-airport, direct visitor, and off-airport impacts to estimate multiplier impacts.
Total Impacts – Total impacts were estimated by summing the direct on-airport, direct visitor, off-airport, and multiplier impacts.
Allegheny County Airport
Direct On-Airport Impacts – Direct employment impacts from the 2007 study are not changed. The direct payroll and output impacts for airport tenants from the 2007 study are inflated to 2010 dollars using BLS’ CPI.
CIP expenditure data for 2008-2010 is estimated to measure direct employment, payroll, and output impacts generated by on-airport construction projects. Employment and payroll impacts associated with CIP expenditures were identified using Pennsylvania-specific employment ratios per $1 million of CIP output from the IMPLAN model and the BLS average state wage for construction-related workers in Pennsylvania.
Direct Visitor Impacts –General aviation visitor expenditures are identified using a similar methodology detailed for this aviation group earlier in this report. The number of annual true transient arrivals based on aircraft operations data from the ACAA is used to
estimate annual visitors. Data regarding average visitor spending from the 2007 study is inflated to 2010 dollars using BLS’ CPI. Employment and payroll impacts associated with general aviation visitor expenditures are identified using Pennsylvania-specific
employment ratios per $1 million of visitor output from the IMPLAN model and the BLS average state wage for workers in Pennsylvania in service sectors.
Multiplier Impacts – Pennsylvania-specific IMPLAN multipliers are applied to the direct on-airport and direct visitor impacts to estimate multiplier impacts.
Total Impacts – Total impacts are estimated by summing the direct on-airport, direct visitor, and multiplier impacts.