Components of the TSAs

Components of the TSAs

Purpose of the TSAs

The TSAs consist of four tables: make (production), use (consumption), direct requirements, and industry-by-commodity total requirements table. The TSAs make and use tables present I-O data with in-house transportation added as an additional commodity and industry. The TSAs direct requirements table shows data on industry use of intermediate and value-added inputs as a percentage of industry output. The TSAs total requirements table provides industry-bycommodity multipliers. The following discusses each table in further detail and presents data at the summary-level. Detailed data can be found in the online appendix to this report: http://www.bts.gov/publications/transportation_satellite_accounts/2011/appendicies. Further information on the units in the make and use tables can be found in box C.

Make Table

The make table in the TSAs (see table 6) is an I-O make table with additional columns for each in-house transportation mode as a commodity and additional rows for each in-house transportation mode as a new industry. As in an I-O make table, the TSAs' make table shows the values, in producers' prices, of each commodity produced by each industry. In each row, the cell on the main diagonal shows the value of the commodity for which the industry has been designated as the primary producer. The other cells in each row show the value of commodities for which the industry is a secondary producer. The sum of all entries in a row is the total output for the industry.

The data in all cells of the TSAs' make table is the same as in the 1997 I-O make table, with the exception of the added in-house transportation column and row for each mode. For each in-house mode, the cell value at the intersection of the in-house transportation column and row equals the total output of in-house transportation; the value for all other cells in the in-house transportation column and row equals zero.

Use Table

Table 7 shows the TSAs' use table, which is an I-O use table with an additional row for the in-house transportation services provided by each in-house mode and an additional column for the redefined in-house transportation activities for each in-house mode. Through this additional column, the TSAs' use table shows the values, in producers' prices, of in-house transportation next to all other intermediate and value-added inputs consumed by other industries or final users. The cell in each row is the amount, as a dollar value, of the commodity used by each industry or final user of the commodity. In the in-house transportation row, the following cells equal zero:

  • the cell at the intersection of each in-house transportation row and column (the use of in-house transportation services to support in-house transportation activities), and
  • the cell values at the intersections between each in-house transportation row and the for-hire transportation columns (the use of the in-house transportation services to support for-hire transportation activities).

These cells take a zero value as in-house transportation services are provided only by nontransportation industries for their own use.

For all rows, the sum of all entries equals the total output of the commodity. For all columns, the sum of all entries equals the total output for the corresponding industry (see box C for further information on total commodity and total industry output).

Direct Requirements Table

The direct requirements table (see table 8) presents the direct requirement coefficients for each commodity and industry. These values show the amount of a commodity (on a row) required by an industry (on a column) to produce a dollar of the industry's output. The sum of the coefficients for an industry for all intermediate and value-added categories equals one.

The direct requirement coefficients in the table are derived from the TSAs' use table by dividing each industry's commodity and value-added inputs by that industry's total output. This is done for all industries in the TSAs' use table but not for the components of final use or GDP.

Industry-By-Commodity Total Requirements Table

Table 9 presents the industry-by-commodity total requirements coefficients. These values show the production directly and indirectly required to deliver a dollar's worth of goods and services to consumers and other final users. Each column shows the commodity delivered to final users, and each row shows the demand for an industry's output in response to a dollar increase in the final demand for the commodity. The values in the columns and rows are derived from the TSAs' make and use tables.

The last row shows the sum of all the changes in industry outputs that are required to deliver a dollar's worth of goods and services to final users. Because each of these sums is a dollar multiple of the initial dollar spent of an industry's output, the sum often is referred to as an "output multiplier." These multipliers can be used to estimate the impact of changes in the final demands of commodities on total industry output.16 Hence, the table shows the interdependence among producers and consumers in the economy and can be used to derive estimates of the direct and indirect effects of changes in final demand on for-hire and in-house transportation industries and commodities. For instance, the table can be used to analyze the relative effects on transportation and nontransportation industries from an increase in government expenditures on transportation or from a change in the composition of fixed investment that results from a change in business activity.17

16 For more information on the derivation of the industry-by-commodity total requirements table, see: United Nations, Handbook of National Accounting--Input-Output Table, Compilation and Analysis, 1999, available at http://unstats.un.org/unsd/EconStatKB/KnowledgebaseArticle10053.aspx as of Mar. 15, 2011.

17 When deriving the TSAs' industry-by-commodity total requirements coefficients, the underlying I-O assumptions were maintained. This includes the assumption that the technology and relative prices defining the relationships between producers and consumers within a given year remain constant. For more information, see: U.S. Department of Commerce, Bureau of Economic Analysis, Concepts and Methods of the U.S. Input-Output Accounts, September 2006, updated April 2009, available at http://www.bea.gov/papers/pdf/IOmanual_092906.pdf as of Mar. 15, 2011.