NAPM index. A measure of the health of the manufacturing sector, and more generally the overall economy, calculated by surveying purchasing managers for data about new orders, production, employment, deliveries, and inventory, in descending order of importance. It is released on the first business day of the month at 10 am EST and reflects the previous month's data. A reading over 50% indicates that manufacturing is growing, while a reading below 50% means it is shrinking. The NAPM index is also thought to be an early indicator of inflationary pressures.