Information Note – Industrial Production and Turnover (IPT) Index Revision – 2021

The CSO’s Industrial Production and Turnover (IPT) Index for October 2021 (published on 13 December 2021) contains revisions to the data series. The revisions to the data have impacted the series from January 2015 to April 2022.

Background – Index Calculation

Individual turnover sub-indices are compiled for each detailed NACE class (i.e. NACE 4-digit level). These sub-indices are combined to provide the indices for broader sectoral groupings (NACE 2-digit and groupings of NACE) using the turnover as the weight. The production indices are created in the same way but use the gross value added at factor cost (GVA) as the weight. The production indices are calculated at constant prices, using the Wholesale Price Index (Base 2015 = 100) as deflators. The base-year GVA and turnover weights are from the 2015 Census of Industrial Production (CIP). The weights and base year are updated every five years. 

Scope of the Revisions

Industrial Production Index

Four issues are included in the revisions to the Industrial Production index; these are outlined in Table 1.

[1] Information Note - Wholesale Price Index Revision 2020

Industrial Turnover Index

In the case of the turnover series, all revisions to the data relate to:

1. Specific identified changes to the raw data: These are routine revisions and there have not been any other process or technical changes to the calculation of the turnover indices.
2. Updates to the seasonal adjustment modelling to take account of these changes to the raw data. Please note that as with the production index, the seasonal adjustment modelling will continue to be kept under review.

Impact of the Series

The impact of the revisions on the production and turnover indices over the past 12 months is set out in Tables 2 and 3 respectively. A comparison over the full time period of the indices, from January 2015, is shown in Graphs 1 and 2 below.

Further data requests or statistical queries:

It should be noted that the scale of the revisions depends on the reference period or sector being analysed. The revised data at the most detailed level are available on CSO’s PxStat. While the previously published data are no longer on the CSO website, this data can be made available to users on request. Please contact the CSO team directly, using the email address below, for further data requests or statistical queries.