The PMI is a composite index based on the seasonally adjusted diffusion indexes for the following five indicators at equal weights:
New Orders, Production, Employment, Supplier Deliveries, Inventories

Source: Institute for Supply Management (ISM)
http://www.ism.ws/files/ISMReport/MfgAllIndexes09.xls

   * New Orders: reflects the levels of new orders from customers.
   * Production: measures the rate and direction of change, if any, in the level of production.
   * Employment: reports the rate of increase or decrease in the level of employment.
   * Supplier Deliveries: reveals if deliveries from suppliers are faster or slower.
   * Inventories: reflects the increases and/or decreases in inventory levels.
   * Customer Inventories: rates the level of inventories the organization's customers have.
   * Prices: reports whether organizations are paying more or less for product(s)/service(s).
   * Backlog of Orders: measures the amount of backlog of orders, whether growing or declining.
   * New Export Orders: reports on the level of orders, requests for services, and other activities to be provided outside of the United States.
   * Imports: measures the rate of change in materials imported.