Notes to Editors
The SMI’s (Sales Managers’ Indexes) are compiled and analysed by World Economics and are based on survey data collected from a panel of companies stratifying all Industry Classification Board (ICB) sectors which are weighted to reflect their contribution to national Gross Domestic Product.
The Sales Managers’ Index results are calculated as diffusion indexes which have the characteristics of leading indicators by taking the percentage of respondents that report that activity has risen (“Increasing") and adding it to one-half of the percentage that report the activity has not changed (“Unchanged"). Using half of the “Unchanged" percentage effectively measures the bias toward a positive (above 50 points) or negative (below 50 points) index. An example of how to calculate a diffusion index: if the response is 40% “Increasing," 40% “Unchanged," and 20% “Reducing," the Diffusion Index would be 60 points (40% + [0.50 x 40%]). A value of 50 indicates "no change" from the previous month.
The more distant the index is from the amount that would indicate "no change" (50 points), the greater the rate of change indicated. Therefore, an index value of 58 indicates a faster rate of increase than an index value of 53, and an index value of 40 indicates a faster rate of decrease than an index value of 45. A value of 100 indicates all respondents are reporting increased activity while 0 indicates that all respondents report decreased activity.
From May 2017, all data in charts and referenced numerically is un-adjusted index data. The three month Moving Averages used prior to this data as a proxy for seasonal adjustments are available via a subscription to World Economics Data. All data is not revised after publication.