The ISM manufacturing index (or PMI - Purchasing Manager's Index before September 2001) is an economic measure for the US business sector. This index is run by the Institute of Supply Management in Arizona, which releases a monthly report on the first working day of the month on the overall state of the business sector in the United States.
The report attempts to gauge how the manufacturing sector of the US economy is doing. For example, it will cover how Ford is doing. This is similar to how the ISM Services Index works. Specifically, it is based on five main indicators:
The Institute of Supply Chain Management sends out surveys every month to these businesses to answer a few simple questions. The survey isn’t just sent out to anyone, but directed towards the people who have the power to buy stuff and hire people. If you aggregate enough of this information you should be able to get a pretty good gauge of the manufacturing sector’s health.
Generally, an ISM value of 50 is considered neutral, a value of over 50 points as an expansion of the manufacturing sector and a value of less than 50 points a decline in industrial production views. The index has an average lead before the actual industrial production three to six months.