ISM® Makes Annual Adjustments to Seasonal Factors for Manufacturing PMI®, Non-Manufacturing NMI® and Diffusion Indexes

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Jan 26, 2018, 10:00 ET

TEMPE, Ariz., Jan. 26, 2018 /PRNewswire/ -- Based on input from an independent expert, Institute for Supply Management^®(ISM^®) recently announced the completion of its annual adjustments to the seasonal factors used in the monthly (ISM^®) Manufacturing Report On Business^® and the monthly (ISM^®) Non-Manufacturing Report On Business^®. Purchasing managers and economists who track these indexes will note that changes are effective with the January 2018 ISM^® Manufacturing Report On Business^®, which is scheduled to be released on February 1, 2018, and the January 2018 ISM^® Non-Manufacturing Report On Business^®, which will be released on February 5, 2018.

Seasonal adjustment factors are used to allow for the effects of repetitive intra-year variations resulting primarily from normal differences in weather conditions, various institutional arrangements, and differences attributable to non-movable holidays. It is standard practice to project the seasonal adjustment factors used to calculate the indexes one year ahead (2018).

As in previous years, the X-13-ARIMA program was used to develop the revisions to the Manufacturing and Non-Manufacturing indexes for March 2006 through December 2017, as well as the 2018 projected seasonal factors. The 2018 seasonal factors will be recomputed when the actual data are known in early 2019. Projected seasonal factors for 2018 are shown below.

2018 Seasonal Adjustment Factors for ISM^® Manufacturing Indexes

	New Orders	Production	Employment	Supplier Deliveries
JAN 18	0.953	0.944	0.976	1.000
FEB 18	1.028	1.015	0.993	1.004
MAR 18	1.088	1.048	0.978	1.012
APR 18	1.098	1.099	1.042	1.002
MAY 18	1.031	1.032	1.033	1.011
JUN 18	1.043	1.030	1.051	0.999
JUL 18	0.981	0.989	1.021	1.005
AUG 18	0.962	0.982	0.999	0.992
SEP 18	0.975	0.971	0.979	1.013
OCT 18	0.949	0.977	0.987	1.001
NOV 18	0.942	0.975	0.980	0.975
DEC 18	0.947	0.939	0.961	0.983

To compute the PMI^®:

1) Calculate the unadjusted diffusion index for New Orders, Production, Employment and Supplier Deliveries (percent higher or slower plus one half of the percent same or unchanged). For Inventories, which are not adjusted, it will be percent higher plus one half of the percent same or unchanged.

2) Divide each unadjusted diffusion index by its seasonal factor.

3) Add all five index numbers together and divide by five.

To compute other indexes, follow steps #1 and #2 above for each indicator.

2018 Seasonal Adjustment Factors for ISM^® Non-Manufacturing Indexes

	Business Activity	New Orders	Employment	Prices
JAN 18	0.919	0.909	0.926	0.985
FEB 18	0.979	0.964	0.982	1.016
MAR 18	1.032	1.008	0.998	1.025
APR 18	1.082	1.075	1.036	1.043
MAY 18	1.020	1.016	1.035	1.057
JUN 18	1.010	1.036	1.083	1.030
JUL 18	1.026	1.026	1.033	1.018
AUG 18	0.997	1.002	0.979	0.972
SEP 18	1.012	1.039	0.977	0.966
OCT 18	0.984	0.976	0.988	0.980
NOV 18	0.989	0.992	0.968	0.957
DEC 18	0.951	0.957	0.994	0.955

To compute the NMI^®:

1) Calculate the unadjusted diffusion index for Business Activity, New Orders and Employment (percent higher or up plus one half of the percent same or unchanged). For Supplier Deliveries, it will be percent slower plus one half of the percent same or unchanged.

2) Divide each unadjusted diffusion index by its seasonal factor.

3) Add all four index numbers together and divide by four.

To compute other indexes, follow steps #1 and #2 above for each indicator.

The revised breakeven points for the overall economy will be released by February 1, 2018.

About ISM^® Report On Business^®The ISM^® Report On Business^® is considered by many economists to be the most reliable near-term economic barometer available. It is reviewed regularly by top government agencies and economic and business leaders for its timely, accurate information. The Manufacturing and Non-Manufacturing ISM^® Report On Business^® is published monthly by Institute for Supply Management^®. Each month, both reports are compiled from responses to questions asked of purchasing and supply executives across the country and reflects change, if any, in the current month compared to previous months.

About Institute for Supply Management^®
Institute for Supply Management^® (ISM^®) serves supply management professionals in more than 90 countries. Its 50,000 members around the world manage about $1 trillion in corporate and government supply chain procurement annually. Founded in 1915 as the first supply management institute in the world, ISM^® is committed to advancing the practice of supply management to drive value and competitive advantage for its members, contributing to a prosperous and sustainable world. ISM^® leads the profession through the ISM^® Report On Business^®, its highly regarded certification programs and the ISM^® Mastery Model™. This report has been issued by the association since 1931, except for a four-year interruption during World War II.

For the full release, please contact Kristina Cahill: [email protected]