1. Luxembourg, 13-14 October 2008 1 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt BACKCASTING OF TIME SERIES: PROBLEMS AND RESULTS Bronislava Kaminskiene Statistics Lithuania

2. Luxembourg, 13-14 October 2008 2 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt SUBJECT-MATTER 1.PECULIARITIES RELATED TO CHANGE OF CLASSIFICATION 2.PRELIMINARY RESULTS 3.PROBLEMS

3. Luxembourg, 13-14 October 2008 3 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt STAGES OF WORK Double survey in 2008 Estimation by NACE-2 re-designing samples of 2005 – 2007 Analyses of the situation and results Testing of methods for backcasting Backcasting time series for the period of 2000 – 2004 Evaluation of results Preparation of final time series

4. Luxembourg, 13-14 October 2008 4 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt THE PROGRESS Estimation of turnover and production at current prices Preparation of weights for price indices Re-calculation of price indices Estimation of turnover and production in price of the base year Preparation of indices of time series Seasonal and working day adjustment

5. Luxembourg, 13-14 October 2008 5 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt PARTICULARITY INDUSTRY – group level (3 digits) TRADE – class level (4 digits) CONSTRUCTION – section level (2 digits) OTHER SERVICES – class level (4 digits) or at a more detailed level

6. Luxembourg, 13-14 October 2008 6 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt CHANGES IN THE POPULATION STS activities NACE 1NACE 2OutcomingIncoming enterprises persons employed enterprises persons employed enterprises persons employed enterprises persons employed Industry Section D 78652502117314 242721 614 (7.8%) 7798 (3.1%) 63 (0.8%) 308 (0.1%) Trade 50 667268092645260484 220 (3.3%) 7608 (11.1%) 00 51 7278781007278781000000 52 130981440061331815161400 220 (1.7%) 7608 (5.3%) Construction54521141576011116103 20 (0.37%) 131 (0.1%) 579 (9.6%) 2077 (1.8%) Other services2456537973524534376146 801 (3.3%) 8096 (2.1%) 770 (3.1%) 4508 (1.2%)

7. Luxembourg, 13-14 October 2008 7 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt RELATIONSHIPS Trade Activity Type of relationships Percentage of enterprises Percentage of persons employed Percentage of turnover 50One-to-one 65.463.362.4 One-to-many 34.636.737.6 51One-to-one 79.676.278.4 One-to-many 20.423.821.6 52One-to-one 76.283.985.3 One-to-many 23.816.114.7

8. Luxembourg, 13-14 October 2008 8 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt CONVERSIONS Trade NACE 1NACE2Number of enterprises Number of persons employed Turnover 5030 4531 0.2180.4700.752 4532 0.7180.5300.248 5143 4643 0.8460.9460.911 4647 0.0860.0280.031 4652 0.0680.0260.058 5245 4743 0.2980.1680.159 4754 0.5790.7800.823 4759 0.0380.0110.009 4763 0.0850.0410.010

9. Luxembourg, 13-14 October 2008 9 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt RELATIONSHIPS Industry, manufacturing Type of relationships Percentage of enterprises Percentage of persons employed Percentage of production One-to-one18.818.318.1 One-to-many75.977.378.2 Many-to-one5.34.43.7

10. Luxembourg, 13-14 October 2008 10 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt CONVERSIONS Industry NACE 1NACE2Number of enterprises Number of persons employed Turnover One-to-many 292 282 0.580.770.84 331 0.350.180.12 332 0.060.050.03 432 0.010.00 Many-to-one 202 162 0.050.210.31 203 0.570.480.43 204 0.180.190.17 205 0.190.120.08 366 0.010.00

11. Luxembourg, 13-14 October 2008 11 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt RELATIONSHIPS Other services Type of relationships Percentage of enterprises Percentage of persons employed Percentage of turnover One-to-one 24.719.426.1 One-to-many 24.118.427.1 Many-to-one 18.822.715.7 Many-to-many 32.439.531.1

12. Luxembourg, 13-14 October 2008 12 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt METHOD USED Model used for backcasting for every time period t In case of many-to-one In case of one-to-many – values of time series to be estimated, group or class i of NACE2 – values of time series of groups or classes incoming t= 1,2,…T – qualified time

13. Luxembourg, 13-14 October 2008 13 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt EVALUATION OF ACCURACY For the period of 2005–2008 – coefficient of variation For the accuracy of models and backcasting – absolute relative error

14. Luxembourg, 13-14 October 2008 14 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt INDUSTRY Manufacturing, 2005 – 2008

15. Luxembourg, 13-14 October 2008 15 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt INDUSTRY Manufacturing, 2000 – 2004

16. Luxembourg, 13-14 October 2008 16 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt ACCURACY SECTION LEVEL Re-estimation – period 2005 – 2008 – coefficients of variation less than 3 % Backcasting – period 2000 – 2004 – relative error less than 2.5% DIVISION LEVEL (2 digits) Re-estimation – period 2005 – 2008 – coefficients of variation less than 5 % Backcasting – period 2000 – 2004 – relative errors in interval (0–6) %

17. Luxembourg, 13-14 October 2008 17 Workshop on Backasting SHORT-TERM BUSINESS STATISTICSwww.stat.gov.lt PROBLEMS Short period for analysis and re-estimation Very high workload of specialists Increased number of “small” strata Small size of samples in some new strata Sample size fluctuate in time New activities composed from many small parts Large fluctuations in the number and activities of enterprises Conversion matrices are not stable