Definition: The Purchasing Managers Index is released on the first day of the month by the National Association of Purchasing Managers. The PMI measures five factors in business: new orders, inventory levels, production, supplier delivers, and employment conditions. Each of these five factors are adjusted and weighed according to time of year and other events.

A PMI over 50% means that manufacturing is growing and expanding.

A PMI under 50% means that manufacturing is declining. a PMI of 42.7% or more over a long period of time means the economy as a whole is expanding. A PMI of 42.7% of below over a long period of time means the economy as a whole is contracting.