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This expert group session explores the methodology for calculating additive contributions to growth in Eurostat's database. The session covers the different methods for overcoming the non-additivity of chain-linked volume estimates and provides step-by-step calculations for the contributions to growth by main components of GDP. The session also includes a comparison of Eurostat's data with Italian data to showcase the consistency of the dissemination process.
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Completing the dissemination with contributions to growth Expert Group on QNA Luxembourg, 20-21 June 2019 Item 8
Eurostat’s database contains not only data transmitted by Member States but also derived indicators such as data in €, growth rates, implicit deflators… • and contributions to growth for European aggregates To highlight which are the main drivers of growth • on a quarterly/annual basis Background
Chain-linked volume estimates of the components of GDP are not additive but… It is possible to calculate the contributions of each component to the growth rate of the aggregate that are additive Chapter on contribution to growth in the Eurostat’s handbook on QNA https://ec.europa.eu/eurostat/web/products-manuals-and-guidelines/-/KS-GQ-13-004 INSEE’s document “Computing additive contributions to growth and other issues for chain-linked quarterly aggregates” https://www.insee.fr/fr/statistiques/2127781 Background on the methodology
The additive case formula cannot be applied to chain-linked volumes as these volumes are not additive by construction • 3 methods overcome the problem: • Additive volume data method(AVD) transform chain-linked volumes into additive measures • Weighted growth rates method (WGR) weights the components’ growth rates • Partial contributions to growth method (PCG) Overview of the methodologies
AVD method for QoQ (quarters 2,3 and 4): • Where : X = GDP • xi = component i of GDP • c = quarter • y = year • CV = chain-linked values • P = deflator • Chain-linked values are multiplied by their deflator • Contribution for changes in inventories calculated as a residual because values positive or negative The recommended methodology (1/3)
adapted method for QoQ (quarter 1): • Q1 is at prices of year y-1 and the previous quarter (Q4) is at prices year y-2 • The second element makes the contributions to growth exactly additive The recommended methodology (2/3)
adapted method for YoY (all quarters): • The second element makes the contributions to growth exactly additive The recommended methodology (3/3)
In Eurobase • For GVA industry breakdown at A10 level • For main expenditure components • for investment (GFCF) breakdown by asset types • Select contributions to growth in ‘Unit of measure’ • In 2 decimals precision • In News release • T+65 GDP News release • T+100 GDP Statistics Explained Dissemination
In 6 tables: • nama_10_gdp and namq_10_gdp • nama_10_a10 and namq_10_a10 • nama_10_an6 and namq_10_an6 • In 2 units : • In percentage point change on previous period (QoQ) • In percentage point change compared to the same period in previous year (YoY) • Precision: • 2 decimal precision in Eurobasefor additivity • 2 decimal precision in GDP NR graph for additivity • 1 decimal in NR table to match growth rate precision Detailed information on contributions to growth disseminated in Eurobase (1)
For various components of GDP: • Final consumption expenditure (gvt + HH&NPISH) • Gross fixed capital formation • Changes in inventories and acquisitions less disposals of valuables • Imports (goods + services) • Exports (goods + services) • External balance of goods and services • On Seasonally and calendar adjusted series (QoQ and YoY) and non-adjusted series (YoY) Detailed information on contributions to growth disseminated in Eurobase(2)
With 1 decimal precision T+65 News release (2/2)
Updated at t+100 days Statistics Explained : Quarterly national accounts - GDP and employment
Step 1 (Eurostat): Apply to National data the same formula used for aggregates Step 2 (Member States): Compare with National calculation Step 3 (Eurostat): Disseminate one of them Completing the dissemination with contributions to growth by Member States
Excel file with step-by-step calculation of the contributions to growth by main components • P3 (final consumption expenditure) • P3_S13 (general gvt) • P31_S1M (Households non-profit institutions serving households) • P5 (gross capital formation) • P51G (gross fixed capital formation) • P5M (Changes in inventories and acquisition less disposals of valuables) • B11 (external balance) • P6, P61 and P62 (exports – goods and services) • P7, P71 and P72 (imports – goods and services) A negative sign is assigned to Imports in order to sum all the contributions to growth Eurostat vs Italian data example (1/4)
Pre-filled excel file with input data and step-by-step calculation of contributions to growth Eurostat vs Italian data example (2/4)
Values transmitted with 3 decimals Comparison on QY only Discrepancies around 0.000 A negative sign is assigned to Imports in order to sum all the contributions to growth Eurostat vs Italian data example(3/4)
Comparison of Eurostat and Italian data suggests that dissemination of data would be consistent • Eurostat will circulate data for all countries • Main expenditure aggregates with step by step calculations of contributions to growth to show method • Method for other aggregates (other breakdowns - GVA GFCF) is similar but derivation steps could also be set if desired • NSI should analyse results and compare with national compilations if available • Agree to dissemination using Eurostat formula if results are consistent The wayforward (1/2)
If results differ; the origin of differences should be clarified (data precision or method) • If MS prefer publishing own data they should send: • G01 an G04 for T0101 and T0102 for AN, QN and QY i.e. contributions to growth and GDP growth rate on QoQ and YoY • Unit: percentage with minimum 3 decimals (to check additivity and avoid rounding difference) • Imports should be send with a negative sign to sum all components (SUM = GDP growth rate) • Validation checks on additivity and consistency with level series would need to be added for validation together with metadata explaining applied method The wayforward (2/2)
EGQNA members are invited to: • Take note of the implemented formula applied to derive contributions to growth by Eurostat and inform on possible differences with nationally published estimates. • Agree to the dissemination of country specific contributions to growth using the method already implemented by Eurostat for European aggregates • Alternatively countries could opt to transmit contributions to growth with sufficient precision and metadata on the method to allow the set up of reliable validation checks Conclusions