Background Notes

Gross Value Added at Constant Basic Prices Nace Rev 2 

This release provides gross value added at current basic prices and constant basic prices (chain linked and referenced to 2017) for the economy divided into two sectors, namely

(a) the economic sectors dominated by Foreign-owned Multi National Enterprises (MNEs)

and

(b) all other remaining sectors.

Gross value added at basic prices is measured as the difference between out­put at basic prices and intermediate consumption at purchasers’ prices.

The sectoral data underlying the aggregates in the release are the same as those used for

1. Gross Value Added for Foreign-owned Multinational Enterprises and Other Sectors Annual Results 2018 (CSO StatBank Table N1823)
   
   and
   
   
2. National Income & Expenditure 2018 (NIE 2018) Table 4 (CSO StatBank Table N1804), which gives a breakdown of the economy at Constant Basic Prices by 10 principal economic sectors (Nace Rev.2 A10) and NIE Table 22 (CSO StatBank Table N1822) which illustrates a 37 sector breakdown of the Irish economy.

The correspondence with the relevant A10 sections of NACE Rev.2 is as follows: 

National accounts are compiled in the EU according to the European System of National and Regional Accounts (ESA) framework. In 2014, the new ESA 2010 framework replaced the ESA 95 version and all EU member states were required to adopt ESA 2010 by September 2014. ESA 2010 is the European version of the current UN mandated international standards for national accounts statistics, the System of National Accounts (SNA) 2008. The results for all years in this release are published on an ESA 2010 basis.

Nace classification

In compliance with EU regulations the contents of the sectors in this release conform to the Nace Rev. 2 system which corresponds with the UN International Standard Industrial Classification (ISIC Rev 4).

For the Foreign-owned MNE dominated sector and ‘Other’ sector variables set out in Tables A and B of this release, the following is the correspondence with the relevant NIE and Nace Rev. 2 sectors:

Volumes

For further information on the Nace Rev. 2 classification of industrial activity, visit the CSO website:

https://www.cso.ie/en/methods/classifications/industrialactivity/

Seasonal Adjustment

Seasonal adjustment is conducted using the direct seasonal adjustment approach. Under this approach, each individual time series is independently adjusted, i.e. aggregate series are adjusted without reference to the component series. This direct approach is applied to the Foreign-owned MNE dominated sector, the combination of all other remaining non-MNE dominated NACE sectors (i.e. the ‘Other’ sector) and the seasonally adjusted values for the total economy are not derived as the sum of the seasonally adjusted components but rather by seasonally adjusting the unadjusted values for the total economy as shown in Table A. On this account, the sum of the seasonally adjusted components of the Foreign-owned MNE dominated and ‘Other’ sectors do not add to the respective seasonally adjusted total economy series. As part of the seasonal adjustment process, ARIMA models have been identified for each series based on unadjusted data spanning Q1 1995 to Q2 2019. These models are then applied to the entire series (Q1 1995 to Q2 2019). Seasonal factors and the parameters of the ARIMA models will be updated each quarter.

The adjustments are completed by applying the X-13-ARIMA model, developed by the U.S. Census Bureau to the unadjusted data. This methodology estimates seasonal factors while also taking into consideration factors that impact on the quality of the seasonal adjustment such as:

• Calendar effects, e.g. the timing of Easter,
• Outliers, temporary changes and level shifts in the series.

For additional information on the use of X-13-ARIMA see
www.census.gov/srd/www/winx13/

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