Presentation on theme: "Annual growth rates derived from short term statistics and annual business statistics Dr. Pieter A. Vlag, Dr. K. van Bemmel Department of Business Statistics,"— Presentation transcript:
Annual growth rates derived from short term statistics and annual business statistics Dr. Pieter A. Vlag, Dr. K. van Bemmel Department of Business Statistics, STATISTICS NETHERLANDS (CBS)
Starting Point 2003: systematic higher annual growth rates derived from annual structural business statistics than from short term statistics
STS versus SBS Similar for short term and annual statistics enterprises >= 50 employees: complete enumeration Different for short term and annual statistics enterprises < 50 employees 1.Short term survey (panel) Annual survey (independent) 2.Short term TO SMOOTH irregularities in MM-growth rates weighted to a population 1 corrected for administrative changes between two successive periods Annual weighted to real populations
STS important points Strata (NACE x size): Y k = w i y i )with w i =N/n -------------------------------------------------------------- Publication (NACE) : Turnover (estimate) Y T = Y k ) Index : I T = I T-1 * (Y T / Y T-1 ) CHAIN INDEX !!
Main explanation: panel approach in short term statistics
Formula index I T = I BASE * ( Y 2 /Y 1 ) * (Y 3 /Y 2 ) * (Y 4 /Y 3) ………………… * (Y T-1 /Y T-2 ) * (Y T /Y T-1) = I BASE * B * ( Y T /Y 1 ) With B = (Y 2 /Y 2 ) * (Y 3 /Y 3 ) ….. * (Y T-1 /Y T-1 ) B = measure for bias
Main explanation: panel approach in short term statistics B = 0,982
Results Approach 1 Retail trade ; annual growth rates at detailed publication levels (2003 -2004) original STS (%) adjusted STS (%) Small aggregates significant different results between original STS and adjustedSTS. Reason: survey too small
CONCLUSIONS Number of enterprises with less than 50 employees in The Netherlands 460.000 Survey: short term statistics 29.000 Survey: annual business statistics 85.000 DUE TO THE SMALL SURVEY SIZE: - Always a trade off between bias and variance. - LESSON LEARNED: order of bias should be known when taking a new methodology into production
New developments 2006: New business register Characteristics of the new register Better adjustment between statistical enterprise units and fiscal enterprise units _____________________________________ Strategy of Statistics Netherlands -> investigating whether growth rates of turnover can be derived from VAT.
Approach Enterprises with more than 50 employees -Data collection by Statistics Netherlands (complete enumeration) Enterprises with 50 or more employees -Growth rates in turnover derived from VAT (statistics: register-based) MONTHLY GROWTH RATE PREDICTS QUARTERLY GROWTH RATE QUARTERLY GROWTH RATE PREDICTS ANNUAL GROWTH RATE
turnover covered by data (4th quarter 2006)
First results: similar seasonal patterns
First results: annual growth rates Expectation: no bias between annual growth rates derived from STS (future) and SBS (future)
First Results: pittfalls adjustments in monthly growth rates BIAS: between estimates after 30 days and after 60 days -> further investigation needed.
CONCLUSIONS IN CURRENT SITUATION -Different in annual growth rates derived from STS and SBS are related to a different methodology -Due to small sampling size: Always a trade off between bias and variance FUTURE -Using VAT-data for small enterprises eliminates the variance problem - By using VAT-data research is focussed on determining reliable monthly growth rates (bias/variance) influence of VAT – specific regulations (bias/variance) quality (current vs. future) (bias/variance) other variables (annual business statistics)