Central Statistics Office

National Accounts

National Accounts,

Central Statistics Office,

Ardee Road,

Rathmines,

Dublin 6,

D06 FX52

National accounts data concern all data produced and disseminated for an economy according to the definitions and guidelines of the European System of Accounts (ESA 2010).

National accounts provide data for the total economy, but may also include breakdowns of the total economy (into economic sectors, industries, products, regions, etc.). National accounts provide data for several domains:  annual and quarterly national accounts (main aggregates), institutional sector accounts, financial and non-financial accounts, supply and use and input-output tables, regional accounts and government finance statistics.

One of the main aggregates of national accounts is the change rate of the price-adjusted gross domestic product (GDP), which indicates the economic development of a country or region and is also referred to as the real economic growth rate.

In Eurobase, EU Member States' data are presented following a common data structure.

At national level, data are commonly available for:

- annual and quarterly national accounts: 'main aggregates'

- annual and quarterly institutional sector accounts, non-financial

- annual financial accounts

- supply and use and input-output tables

- annual and quarterly government finance statistics data: 'main aggregates', quarterly financial government accounts and government debt

- regional breakdowns of main national accounts variables

- industry breakdowns of main national accounts variables

- industry by asset breakdowns (stocks)

The ESA 2010 provides a methodology on common standards, definitions, internationally harmonised classifications and accounting rules that are used for compiling national accounts on comparable bases.

The ESA 2010 defines classifications to be used for: institutional sectors, transactions in products, transactions in non-financial non-produced assets, distributive transactions, transactions in financial assets and liabilities, other changes in assets, balancing and net worth items, balance sheet entries, non-financial assets, financial assets and liabilities.

In addition, for several breakdowns ESA 2010 makes use of other specific classifications: NACE Rev. 2 for economic activities, CPA 2014 for products by economic activities, COFOG for the functions of government, COICOP for individual consumption by purpose, COPNI for classification of the purposes of non-profit institutions serving households, NUTS 2013 for regional breakdowns.

A full overview of classifications is available in:

- ESA 2010 Chapter 23 Classifications

- Eurostat's RAMON classification database

National accounts describe the total economy of a country. All units that have their centre of predominant economic interest in the economic territory of that country are covered.

In addition, several breakdowns of the total are described. Two of the most important are the breakdown by institutional sector and the breakdown by NACE Rev. 2 economic activity. Exhaustiveness is required for each of the breakdown items.

Concerning the institutional sector breakdown, ESA 2010 distinguishes five mutually exclusive domestic institutional sectors: (a) non-financial corporations; (b) financial corporations; (c) general government; (d) households; (e) non-profit institutions serving households. The five sectors together make up the total domestic economy. Each sector is also divided into subsectors. A "rest of the world" sectoral classification is also contained within the ESA 2010 accounting framework that provides an overall view of the economic relationships linking the national domestic economy with non-resident institutional units.

Regarding the economic activity breakdown, ESA 2010 applies NACE Rev.2. Activities can be broken down into several levels of disaggregation of the national economy; for example into 3, 10, 21, 38, 64 or 88 sectors of economic activity. At the 'highest' level a breakdown into 3 categories of activity is defined: (a) agriculture, forestry and fishing; (b) mining and quarrying, manufacturing, electricity gas steam and air conditioning supply, water supply, sewerage, waste management and remediation activities, construction; (c) services.

All statistical concepts and definitions to be used in national accounts are described in Annex A of the ESA 2010 Regulation (link to blue book on ESA2010 methodology). The two main sets of tables concern: (a) the institutional sector accounts; (b) the input-output framework, and the accounts by industry.

The sector accounts provide, by institutional sector, a systematic description of the different stages of the economic process: production, generation of income, distribution of income, redistribution of income, use of income and financial and nonfinancial accumulation. The sector accounts also include balance sheets to describe the stocks of assets, liabilities and net worth at the beginning and the end of the accounting period. The variables/concepts described in the sector accounts include transactions in products, transactions in non-produced non-financial assets, distributive transactions, transactions in financial assets and liabilities, other changes in assets, non-financial and financial assets and liabilities.

The input-output framework, through the supply and use tables, sets out the production process in more detail (cost structure, income generated and employment) and the flows of goods and services (output, imports, exports, final consumption, intermediate consumption and capital formation by product group). These variables are broken down by industry (NACE Rev. 2) and product (CPA 2014).

ESA 2010 also encompasses concepts of population and employment. Such concepts are relevant for the sector accounts, the accounts by industry and the supply and use framework.

Regional accounts provide regional breakdowns for major aggregates such as gross value added and household income. These are based on the NUTS classification. National accounts concepts are also used for regional accounts.

In addition Annex A of the ESA 2010 Regulation addresses and defines numerous other concepts and definitions, such as the definition of: statistical units and their groupings (see also Section 3.5 below), flows and stocks, accounting rules (valuation, time of recording, consolidation and netting).  The main features and principles for the compilation of national accounts can be found in Chapter 1.

Following the ESA 2010 guidelines, two types of units and two corresponding ways of subdividing the economy are used for national accounts purposes: (a) institutional unit; (b) local kind-of-activity unit (local KAU). The first type is used for describing income, expenditure, output and financial flows as well as balance sheets. The second type of units is used for the description of production processes, for input-output analysis and for regional analysis.

An institutional unit is an economic entity characterised by decision-making autonomy in the exercise of its principal function. A resident unit is regarded as constituting an institutional unit in the economic territory where it has its centre of predominant economic interest if it has decision-making autonomy and either keeps a complete set of accounts, or is able to compile a complete set of accounts.

A local KAU groups all the parts of an institutional unit in its capacity as producer which are located in a single site or in closely located sites, and which contribute to the performance of an activity at the four digit class level of NACE Rev. 2.

An institutional unit comprises one or more local KAUs; a local KAU belongs to one and only one institutional unit.

The national accounts population of a country consists of all resident statistical units (institutional units or local KAUs, see section 3.5). A unit is a resident of a country when it has a centre of predominant economic interest on the economic territory of that country, that is, when it engages for an extended period (one year or more) in economic activities on this territory.

National accounts are exhaustive. This means that all resident statistical units are covered.

The reference area for national accounts is the total economy of a country. The total economy of a country can be broken down into regions. The NUTS classification provides a single, uniform breakdown of the economic territory of the Member States of the EU.

National accounts data are usually compiled for years and quarters.

In general, the ESA 2010 transmission programme requires data starting in 1995 (years) and 1995Q1 (quarters) but some series start later. If backwards data (more commonly known as "backdata") exist, they may have been compiled according to earlier versions of ESA and can present conceptual breaks with those compiled under ESA2010. 

In Ireland data are available nationally for our main aggregates from 1970 (on an ESA 95 basis for 1970 to 1995 data except for the treatment of Financial Intermediation Services Indirectly Measured [FISIM][It has not been possible for CSO to make estimates of FISIM for years prior to 1995 due to insufficient data availability], on an ESA 2010 basis for years starting from 1995 and onwards [inclusive of FISIM estimates]).

The concept of 'base period' is not applied in national accounts (even though many source data used for national accounts compilation purposes are compiled on a base period basis, e.g. 2015 = 100). Instead, for some national accounts variables the concepts of previous year prices and chain-linked volumes are applied, as stipulated in Commission Decision 98/715/EC. Expressing variables at the prices of the previous year allows the calculation of volume indices between the current time period and the previous year. After a reference period is chosen as a benchmark, volume indices can be chain-linked and then applied to variables at current prices of the benchmark year. This generates volume estimates for any period of observation.

Ireland currently uses 2016 as reference year for the compilation of chain-linked volumes for the annual NIE 2017 accounts (as published in July 2018) i.e. T - 1 year, and this T - 1 year basis holds for each NIE (so chain linked volumes in NIE 2018 will be to reference year 2017 and so on). The method to compile quarterly chain-linked volumes is the annual overlap method. Further details on the Annual Overlap Method are available in the Eurostat Handbook on quarterly national accounts, 2013 edition, Chapter 6. Further details on Chain Linking are available in the OECD publication Understanding National Accounts by François Lequiller & Derek Blades, 2nd Edition (2014).

With the exception of some variables concerning population and labour that are usually expressed in number of persons, hours or jobs, the ESA 2010 system shows all flows and stocks in monetary terms: in euros or other national currency. Flows and stocks shall be measured according to their exchange value, i.e. the value at which flows and stocks are in fact, or could be, exchanged for cash. Market prices are, thus, the ESA's reference for valuation.

In addition to measurement in current (market) prices, some national accounts variables are also expressed in previous year's prices and chain-linked volumes, see section 3.9 above. Furthermore, it is possible to derive growth rates and indices, and various other measures and metrics '(e.g. percentages, per capita data, data expressed in purchasing power standards)' can be applied as well.

The usual reference period to be used for presenting national accounts data is the calendar year for annual data and the quarter for quarterly data.

Two basic kinds of information are recorded: flows and stocks. Flows refer to actions and effects of events that take place within a given period of time (year or quarter), while stocks refer to positions at a point of time (usually the beginning or end of a year or quarter).

National accounts are compiled in accordance with the European System of Accounts (ESA 2010) which was published in the Official Journal as Annex A of Regulation (EU) No 549/2013. The ESA 2010 transmission programme is covered in Annex B

The ESA 2010 has the form of a Regulation and it provides for:

• a methodology (Annex A) on common standards, definitions, classifications and accounting rules that shall be used for compiling accounts and tables on comparable, harmonised bases (link to blue book on ESA 2010 methodology);
• a programme of data transmission (Annex B) setting out the time limits by which Member States shall transmit to Eurostat the accounts and tables (link to ESA 2010 transmission programme).

Temporary derogations to certain elements of the data transmission requirements have been granted to Member States, up to 2020, by the Commission Implementing Decision 2014/403/EU of 26 June 2014 thus allowing national data to deviate temporarily from the ESA 2010 transmission requirements.

Some other legal acts with relevance for national accounts concern:

- Commission Decision 98/715 of 30 November 1998 and Commission Decision 2002/990 of 17 December 2002 on measurement of price and volumes in national accounts.

- Legal act on the excessive deficit procedure

Several separate acts, often regarding classifications such as: NACE Rev.2, CPA 2014, COFOG, COICOP, NUTS 2016 (see also Section 3.2 above).

Other legal acts relevant to national accounts compilation can be found on the Eurostat website under sections 'National Accounts' and 'Government Finance and EDP'.

Irish statistics are compiled under the Statistics Act, 1993.

The Statistics Act, 1993 provides a modern legislative basis for the compilation and dissemination of official statistics. The Act came into operation on 1 November 1994. It incorporated, inter alia, the following provisions:

• the establishment on a statutory basis of the Central Statistics Office (CSO) as an independent Office under the aegis of the Department of the Taoiseach (Irish Prime Minister);
• the functions of the CSO, including in addition to its basic mandate the obligation to co-ordinate official statistics compiled by public authorities, the right to assess the statistical potential of the records maintained by public authorities and to ensure that this potential is realised in so far as resources permit;
• the appointment on a formal basis of the Director-General of the CSO who, in addition to being responsible for the management of the Office, shall also be independent on statistical matters (i.e. sole responsibility for the statistical methodologies and professional standards to be followed, the content of statistical releases and publications, and the timing and methods of dissemination of the statistics compiled);
• the establishment of a National Statistics Board to guide, with the agreement of the Taoiseach, the strategic direction of the CSO;
• the right of access, subject to certain limitations and conditions, of the CSO to administrative records held by public authorities for statistical purposes; and
• the obligation on the CSO to treat all individual information relating to persons or concerns as strictly confidential and to use such information solely for statistical purposes.

The Act fully reflects the Fundamental Principles of Official Statistics adopted by the UN Economic Commission for Europe in 1992.

National accounts data are key datasets used and published by many international organisations to improve data consistency across countries and exploit synergies for data collection and validation. An initiative to improve data sharing for National Accounts was launched in 2016 by the Inter-Agency Group on Economic and Financial Statistics (comprising representatives of the Bank for International Settlements, the European Central Bank, Eurostat, the International Monetary Fund (IMF), the Organization for Economic Co-operation and Development (OECD), the United Nations, and the World Bank)  under the G20 Data Gap Initiative.

Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society. The European Statistics Code of Practice provides further conditions that have to be respected by statistical offices in regard to statistical confidentiality (Principle 5).

All information supplied to the CSO is treated as strictly confidential. The Statistics Act, 1993 sets stringent confidentiality standards: Information collected may be used only for statistical purposes, and no details that might be related to an identifiable person or business undertaking may be divulged to any other government department or body.

These national statistical confidentiality provisions are reinforced by the following EU legislation:

• Council Regulation (EC) No 223/2009 on European statistics for data collected for EU statistical purposes.

Further details are outlined in the CSO's Code of Practice on Statistical Confidentiality.

In a statistical sense, ‘confidential data’ means data which allow statistical units to be identified, either directly or indirectly, thereby disclosing individual information. To determine whether a statistical unit is identifiable, account shall be taken of all relevant means that might reasonably be used by a third party to identify the statistical unit. Although national accounts data are usually highly aggregated, there may be cases where statistical units may be identifiable in detailed breakdowns of aggregates and/or in those data in respect of small economies. In these cases measures should be taken in order to ensure non-disclosure of data for a separate statistical unit. Guidance on how to prevent disclosure can be found in the European Statistical System's ESSNet SDC Handbook on Statistical Disclosure Control.

European Statistical System (ESS) good practice requires that new national accounts data and associated news releases are announced in a release calendar that is published sufficiently in advance of the respective release dates.

The release calendar is distributed to the press and to the general publc via the web site.

Release calendars should be easily available and accessible for users, e.g. by publication on the website of a National Statistical Institute (NSI).

The CSO release calendar is available on the website and shows release dates for the coming year on a rolling 12 month basis.

In line with the Community legal framework and the European Statistics Code of Practice (Principle 6 on impartiality and objectivity, Principle 13 on timeliness and punctuality and Principle 15 on accessibility and clarity), national accounts data that meet the quality standards, including relevant metadata, should be made available to users. Users should be informed when data become available and how they can be accessed.

New quarterly national accounts data are published each quarter: four times per year. The full time series of Seasonally & Calendar Adjusted data are usually revised in a given reference quarter with the addition of one extra quarter's unadjusted/underlying data. However, depending on circumstances and national practices, initially released non-seasonally adjusted quarterly national accounts data may be revised and disseminated again at the time of the publication of data in respect of the next subsequent reference quarter (for Ireland, non-seasonally adjusted data for the reference quarters of the current calendar year are the only quarters revised when the Q2, Q3 & Q4 reference quarters results are being issued with prior non-seasonally adjusted backdata being held constant; backdata revisions for reference quarters prior to the current calendar year only take place at the time of issue of the Q1 reference quarter results). Annual national accounts data are published at least once a year: when data for a new year are added and backdata potentially revised. But, depending on country practices and revision policy, annual data can also be published more often, e.g. publication of a provisional estimate early in the calendar year (i.e. a set of "sum of the four quarters" estimates in respect of a given reference year following the publication of Q4 reference quarter data) and a revised one later in the calendar year.

The CSO publishes quarterly national accounts each quarter. Annual national accounts are published along with quarter one reference quarter quarterly national accounts and quarter one balance of payments at the end of June each year.

Each publication of national accounts data by the CSO is accompanied by a press conference and a press release on the day of publication. Exact release dates are pre-announced in a release calendar on the CSO website (see section 8.1 above). The most important or significant aspects of national accounts results are further detailed in associated news releases. 

In addition to news releases, national accounts data may be disseminated in other publications, such as statistical papers, yearbooks, internal and external articles. Usually this concerns publications in which more in-depth analysis is carried out.

The CSO publishes a variety of data related to national accounts including Institutional Sector Accounts, Estimates of Irish Pension Liabilities and Estimates of the Capital Stock of Fixed Assets. These are all available on the CSO website.

In order to enable easy access to national accounts data, all validated national accounts data should be made available to users by publishing them in an online database.

The CSO's database is called Statbank and can be accessed through a web browser. It is also possible to access Statbank through an API in JSON-stat format. There is more information available on this on the CSO website.

Not applicable.

In addition to news releases and other publications (see sections 10.1 and 10.2), information on national accounts may be disseminated using social media.

The CSO has a presence on YouTube, Facebook and Twitter and National Accounts information is routinely posted there.

The general methodological framework for the compilation of national accounts in the EU is ESA 2010.

In addition, several handbooks have been developed to help compilers to produce national accounts data. Some of the most important methodological manuals are the Eurostat Handbook on quarterly national accounts, Eurostat Manual on regional accounts methods, Eurostat Manual of Supply, Use and Input-Output Tables, Eurostat Manual on Government Deficit and Debt. Also, guidance manuals on specific topics are available, e.g. compilation guide on land estimation, compilation guide on inventories, Eurostat Manual on measuring Research and Development in ESA 2010, Eurostat Handbook on prices and volumes measures in national accounts, 2016 Edition.

The manuals above specifically apply to EU national accounts statistics. However, world-wide equivalents are often also available: SNA 2008 (System of National Accounts 2008, a publication produced under the auspices of the UNSD, EU, IMF, OECD & World Bank), IMF Quarterly National Accounts Manual 2017 Edition, UNSD Handbook on Input-Output Table Compilation and Analysis, IMF Government Finance Statistics Manual.

The importance of national accounts requires that documentation should be available on the procedures applied for quality management and quality assessment. Examples of such documentation are national accounts quality reports, quality studies and reports on revision analysis.

Quality of national accounts data is assured by strict application of ESA 2010 concepts and by applying the guidelines of the European Statistical System's (ESS) handbook for quality reports.

During the overall compilation process, national and regional accounts data undergo several kinds of quality checks, e.g. ex-ante (source statistics), ongoing (results), ex-post (methods used) and external checks (Eurostat, European or national Court of Auditors, IMF).

The most recent quality report for Ireland can be found here.

National accounts data provide key information for economic policy monitoring and decision making, for forecasting, for administrative purposes, for informing the general public about economic developments (directly or indirectly via news and media agencies), and as input for economic research.

At national level, the Department of Finance, scientific and academic communities and economic researchers are the entities who most use national and regional accounts data. 

National Accounts are also used by many international institutions such as Eurostat, the European Commission directorates, inter alia DG ECFIN, the European Central Bank (ECB), the IMF, OECD and UN.

Views and opinions of users of national accounts statistics can be collected and analysed as one of the tools to 'measure' the relevance of national accounts data.

The CSO holds regular meetings with a group of national accounts users in the form of the Macroeconomic Statistics Liaison Group. More information on this group is available on the CSO website.

In most countries national accounts cover the domains national accounts main aggregates, government accounts, institutional sector accounts regional accounts and supply and use tables. However, the content of the data on these domains as well as the (details of the) various breakdowns (by region, sector, industry, product, etc.) may deviate per country, depending on specific national user needs and available data sources.

The ESA 2010 transmission programme, consisting of 22 tables across all national accounts domains (see section 10.3 above) defines the minimum harmonised national accounts data set that must be available in all Member States of the EU.

The most recent quality report for Ireland can be found here.

Not applicable.

Not applicable.

National accounts data should become available to users in as timely a manner as possible, taking into account the frequency of the data (annual or quarterly), the character of the data (information on the structure of an economy) and an adequate balance between accuracy and timeliness.

The ESA 2010 transmission programme defines the required timeliness for all national accounts tables. Quarterly tables should become available between 2 and 3 months after the quarter-end. The first iteration of annual tables have to be transmitted to Eurostat between 2 and 3 months (main aggregates) and 36 months (supply and use tables) after the end of the reference year.

Good practice requires that the dates on which national accounts data become available are pre-announced and that the pre-announced publication dates are met.

National accounts data transmissions in the framework of the ESA 2010 transmission programme should be punctually delivered to Eurostat at the timeliness defined in the transmission programme (or before if feasible).

The geographical comparability of national accounts in Member States of the EU is ensured by the application of the common definitions of the European System of Accounts ESA 2010). Worldwide geographical comparison is also possible as most non-European countries apply the SNA 2008 guidelines, and ESA 2010 is broadly consistent with SNA 2008.

As CSO National Accounts data for all reference periods are compiled according to the definitional requirements of the ESA 2010, the data published are fully comparable over time. Also, in the case of fundamental changes to methods or classifications, revisions of long time series are performed, going back to reference year 1995 where required to ensure full temporal consistency.

Within the system of national accounts there is full consistency between the domains: annual and quarterly national accounts, government accounts, sector accounts, financial accounts, regional accounts, supply and use tables. However, in practice perfect alignment may not always be possible and temporary discrepancies might occur. These are usually as a result of vintage differences.

Primary statistics like structural business statistics (SBS), short term statistics (STS) and labour force statistics (LFS) are widely used as input for national accounts. However, there is no full consistency between these statistical domains and national accounts. The main reasons for divergence are differences in concepts/definitions and in coverage. Balance of payments is also used as an important data source for national accounts. The definitions and coverage of balance of payments, as defined in the IMF BPM6 manual (Balance of Payments Manual, sixth edition), are fully harmonised with those in ESA 2010. Therefore, balance of payments variables are in principle fully coherent with the corresponding national accounts variables.

See section 15.3 (Coherence - cross domain).

Not available.

National accounts data are subject to periodic revisions as new input data become available. They are called routine revisions and entail revisions of country data and consequently these necessitate revisions to European aggregates by Eurostat, which are derived from the former. (Routine revisions occur periodically across all EU-28 Member States as a matter of course when improved or more up to date source data become available).

More rarely, exceptional revisions (called benchmark revisions) will result from major changes in data sources, classifications or methodology. For example, when changing from ESA95 to ESA 2010, a benchmark revision occurred at country level across all EU-28 Member States and at euro area/EU aggregate level.

Two European Task Forces developed proposals for a more harmonised approach for benchmark and routine revisions. One under the auspices of the Directors of Macroeconomic Statistics (DMES) dealt with benchmark revision policy, while the other under the auspices of the Committee on Monetary, Financial, and Balance of Payments Statistics (CMFB) worked on the European Harmonised Revision Policy dealing with routine revisions. 

The CSO revises data each year where appropriate/required and does not normally distinguish between benchmark and routine revisions except in cases of major methodological changes like the move from ESA95 to ESA2010.

While revisions should be seen as a process to progressively improve the quality of national accounts as e.g. better sources and/or methods become available, the availability of metadata on revisions is a key element for understanding  national accounts data and the revisions implemented between consecutive releases.

Therefore, information on the main reasons for revisions and their nature (new source data available, new methods, etc.) as well as possibly quantitative and qualitative assessment on the average size of revisions and their direction based on historical data is required.

Ireland performed no major routine or benchmark revisions in respect of the backdata published with 2017 reference year data in NIE 2017.

National and regional accounts compilation are based on statistics that are primarily collected for other purposes (primary statistics) or administrative data sources.

They rely on a variety of data sources, including administrative data: car and business registers, accounting statements, tax data, budgetary reports, population censuses, statistical surveys of businesses and households, statements of supervising institutions and branch organisations, annual and quarterly reports, trade statistics on goods and services, balance of payments information.

There is no single survey source for national accounts. Sources vary from country to country and provide statistical information on a large set of economic, social, financial and environmental phenomena, which may not be all relevant to the compilation of national accounts.

Sources and collection methods used in each country vary depending on the specific dataset.

Overall, it is extremely difficult to be fully exhaustive in the listing of data sources. Inventories provided to Eurostat usually include information on main sources (see section 10.6 above). Further information on data sources can be found on the website of National Statistical Institutes (NSIs).

National accounts are usually compiled on an annual or quarterly basis from primary statistics or administrative data sources. The frequency of data collection of primary statistics varies according to the nature of the data source. For example, business statistics are typically available on a monthly (and quarterly) basis. Some households' surveys are available on quarterly or annual frequency (sometimes even less frequently). Availability of administrative data varies from country to country. Population censuses are mostly collected every decade. Ireland however has traditionally collected census data every five years since the census of 1946, albeit with two exceptions (the 1976 census was cancelled as a government economy measure with one held with a restricted number of questions in 1979 instead, and the 2001 census was postponed until 2002 due to the agricultural foot and mouth disease situation that pertained at the time). Census data affect the National Accounts due to the revisions to Labour Force Survey data that occur on foot of each census.

The frequency and timing of the compilation of national accounts are not necessary aligned with the frequency and timing of (all) primary statistics data collections. Of necessity this can lead to the imputation and extrapolation of certain micro data time series (or interpolation using proxies for certain quarterly time series that may be unavailable due to timing issues). Significant efforts are made in data collection and compilation to ensure that these estimates are kept to an absolute minimum in quantity and value terms within the accounts.

National accounts departments typically receive/collect information in relation to their compilation schedule, i.e. for the compilation of their annual or quarterly estimates. 

The data collection is very country specific and also varies according to the nature of the data source, e.g. administrative data, tax and car registers, surveys, accounting statements.  Guidance can be found in the Handbook of Recommended Practices for Questionnaire Development and Testing Methods in the ESS.

In Ireland a wide variety of sources are utilised in the compilation of our National Accounts. We receive data from other CSO divisions including business statistics, balance of payments and agriculture. We also receive administrative data from a variety of external sources including the Revenue Commissioners and the Department of Finance. Certain direct data collection does however take place within CSO National Accounts Divisions. This varies from a handful of small specific surveys such as our Annual Offshore Oil and Gas Exploration Survey to our Large Cases Unit which manages all of the surveys for our largest companies, including the large multinational enterprises (MNEs) operating in Ireland.

Data validation refers to any activity aimed at verifying that the value of a data item is as accurate and precise as is feasible within the compilation time, staffing and other resource constraints. It is a key task performed in all statistical domains and particularly important for national accounts, which is a key dataset for economic analysis and policy decisions.

In order to increase overall data quality and workflow efficiency, the European Statistical System (ESS) is moving towards more harmonisation of validation activities including the definition of common standards, tools and support for implementation (see ESS validation website). National accounts are participating in a pilot exercise in this area. An ESA 2010 Task Force on validation was established in 2015 to agree and document validation rules in an ESA 2010 validation handbook and progressively implement them in a pre-validation service for national accounts data.

The confrontation of data from different sources (where multiple sources are available for a particular economic variable) is an integral part of the national accounts compilation. Source data used in national accounts undergo a sequence of checks within NSIs. For the validation of national accounts data, Ireland applies validation rules agreed with Eurostat and provides metadata to support the validation process with respect to revisions and statistical data outliers. Further information on validation checks can be found on the CSO website.

Data sources, methods and compilation techniques are country specific, but should be employed in such a way that the definitions and concepts contained in ESA 2010 are implemented as closely as possible. Many guidance documents on general and specific national accounts compilation issues are available. For more details see Section 10.6 above.

Key approaches and techniques for the compilation of national accounts in Ireland can be summarised as follows:

The leading approaches to compile GDP in the framework of annual national accounts in Ireland are the income and expenditure approaches. These approaches are produced independently and there is no automatic balancing involved. In examining the validity of the various components of each approach we compare and contrast the results with information available from a wide range of other sources, especially the CSO's short-term indicators and structural inquiries. The components of the two original estimates are shown unadjusted in the published National Income and Expenditure (NIE) accounts. The official level of GDP is taken to be an average of the expenditure and income estimates and a balancing item (statistical discrepancy) is displayed within the relevant NIE tables which is half of the difference between the two estimates. A similar approach is used for the compilation of quarterly national accounts using output and expenditure estimates. Sector accounts are finalised after compilation of the main National Accounts aggregates has been concluded; sector accounts results are fully aligned with the National Accounts Income and Expenditure results.

The objectives of seasonal adjustment are to identify and remove seasonal fluctuations and calendar effects which can mask short and long-term movements in a time series and impede a clear understanding of underlying economic phenomena. Seasonal adjustment is therefore a fundamental process in the interpretation of time series to inform policy making (ESS guidelines on seasonal adjustment, 2015 Edition, Annex, point 1).

For selected sub-annual national accounts data, such as the main quarterly aggregates notably, time series are usually not only published in their unadjusted form, but also on a Seasonally and Calendar Adjusted basis.

The provision of quarterly data that only include calendar adjustments is voluntary.

For sector accounts, seasonal adjustment (including calendar adjustments, where relevant) is compulsory for a limited set of series.

For Ireland 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 GDP and GNP and the seasonally adjusted GDP and GNP are not derived as the sum of the seasonally adjusted components (such as Personal Consumption, Exports etc.) but rather by seasonally adjusting the unadjusted values of GDP and GNP. On this account, and also because of the statistical discrepancy in the original unadjusted data series, the sum of the seasonally adjusted components of GDP and GNP do not add to the respective seasonally adjusted GDP and GNP series. As part of the seasonal adjustment process, ARIMA models are identified for each series based on unadjusted data spanning Q1 1995 to the most recent Q1 reference quarter. These models are then applied to the entire series (Q1 1995 to the current quarter). Seasonal factors and the parameters of the ARIMA models are 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 https://www.census.gov/srd/www/winx13/

No additional comments.