Contribution to the joint OECD/Eurostat Task Force on “Performing Revisions Analysis for Sub-Annual Economic Statistics” Leendert Hoven Statistics Netherlands Using results from revisions analysis to improve compilation methods: a case study on revisions of Dutch estimates of GDP volume growth

Subsequent estimates of GDP growth Quarterly Accounts, flashafter 45 days Quarterly Accounts, regularafter 90 days Yearly estimate, based on QAApril t+1 National Accounts, provisionalJuly t+1 National Accounts, revised provisionalJuly t+2 National Accounts, finalJuly t+3

Summary statistics mean revisionmean absolute revision Flash – QA regular QA regular – NA 1st annual estimate NA 1st annual estimate – NA provisional 0, NA provisional – NA revised provisional 0.040,22 NA revised provisional – NA final Flash – NA final

Graph 3. Mean revision and mean absolute revision between consecutive estimates of GDP volume growth, 1990 – 2003

Average contribution of components to revision of GDP growth between QA regular and NA final, production approachweight %contribution % agriculture, hunting, forestry, fishing315 mining & quarrying27 industry15-4 electricity, gas & water2-3 construction5-18 wholesale, retail trade, repair, hotels &restaurants 1430 transport, storage, communications720 financial intermediation & business services 2435 government1110 banking services1012 health & social care, other services101

Average contribution of components to revision of GDP growth between QA regular and NA final, expenditure approachweightcontribution household final consumption expenditure 4951 government consumption expenditure 24 gross fixed capital formation exports minus imports 415 changes in inventories 027

Two important findings  biggest mean revision between revised provisional estimate and final estimate. Quite large differences between short-term statistics and structural business statistics. Methodological shortcomings (matched pairs approach sts insufficiently allows for effects of population dynamics).  within production approach, commercial services and trade have contributed most to the revisions of GDP growth; short-term source situation particularly bad.

How can we improve early estimates?  improve methodology short-term statistics  improve short-term source situation for commercial services and trade  more research needed on: ovalidity different assumptions; oeffects of balancing process; o ……………….. o

Bias correction at the aggregate level?  no guarantee that average bias of past period will also hold in the future  ignores the underlying data and subaggregates  impact of introduction mew methodologies, changes in data collection, sampling or data processing difficult to capture in the short term