Every transaction on uShip’s unique auction platform represents a market price where supply and demand are in equilibrium. Due to the wide variety of shipments in the uShip marketplace, it is necessary to distill every transaction down to measures of price, weight and distance. We express the price of each shipment in terms of US$ per ton-mile. Every month, we calculate the weighted average of these prices across all of our domestic (US) shipments to determine the overall TPI number for that month.
The nature of transportation services varies widely across categories; therefore, pricing (in terms of US$ per ton-mile) can be very different from one category to the next. It is important to note that the overall TPI number represents a weighted average for our categories, which is a different category mix than the overall US economy.
While the overall number is useful for looking at macroeconomic trends, it is inherently biased by our changing category mix. Therefore, we allow you to filter the TPI by category to get a more accurate picture of how prices have changed for specific types of goods.
By default, the TPI is adjusted for inflation (historic prices converted into current dollars) so that it will only show changes in transportation prices due to other industry dynamics. Also, statistical outliers are removed from our data.