Indices of turnover in services in the Republic of Serbia

Statistical Office of the Republic of Serbia

Two organizational units take part in the activities on the variable Turnover in services. All relevant information relating to the Catering activity are marked with A), and for other sections covered by the mentioned indicator with B).

Information that is in common for both organizational units will not be specially marked.

A) Catering and tourism statistics Group

B) Structural business statistics Unit

A) Bosko Trmcic

B) Gordana Zamaklar

A) Head of Division for Trade, Catering Trade and Tourism Statistics

B) Statistician methodologist for Quarterly Structural Business Statistics

Republic of Serbia, Belgrade, Milana Rakica 5

A) bosko.trmcic@stat.gov.rs

B) gordana.zamaklar@stat.gov.rs

A) (+381) 11 2411 922

B) (+381) 11 2412 922/ 352 ext

A) (+381) 11 2411 922

The turnover index for services is an important indicator for monitoring the dynamics of movements in this part of non - financial economy as well as for short term forecasts. Services turnover indices are derived by combination of data on turnover from three statistical surveys that are based on random samples and administrative data (Tax Administrative Data Base). The statistical surveys are:

A) Quarterly Surveys on Catering Trade (UG-11, UG-11P forms) provide the data on turnover generated by the enterprises through the sale of accommodation, food and beverages, and other services accompanying basic accommodation food and beverages services.
In order to achieve these goals, the following data are collected by surveys:
• turnover in the observed quarter by months;
• turnover generated by catering activities by statistical territorial units (NSTJ 2);
• the structure of turnover generated from catering activity by types of catering services.
B) Quarterly Structural Business Survey (SBS-03 form) provides data on financial operations of enterprises which is based on: operating income, operating costs and stocks. Within "Operating income", data for "Revenues from sales of goods, products and services" is collected, which in fact represents turnover.
Since 2017, the questionnaire was extended with questions on monthly turnover (Revenues from sales of goods, products and services) for the reporting quarter. The monthly estimates of turnover are calculated by domains that comply with the European Business Statistics Regulation (EBS).
These surveys refer to enterprises that in the legal world correspond to legal persons, with  the exception  of the Quarterly Survey on Catering Trades (form UG-11P), which refers only to unincorporated enterprises. For unincorporated enterprises in other NACE Rev. 2 divisions, data is extracted from the tax data base.
The indices are computed by combining estimates on turnover from these three surveys and tax data.
Production of these indices and metadata is the result of implementation IPA 2012 Multi-beneficiary Statistical Cooperation Programme, subproject 13 Short-term business statistics.

The National Classification of Activities - KD (2010), that completely corresponds to the Statistical classification of economic activities in the European Community (NACE Rev.2):

http://www.stat.gov.rs/media/2319/zakon-o-klasifikaciji-delatnosti.doc

The surveys listed under item 3.1 have the following coverage:
A) Quarterly Surveys on Catering Trade (UG-11, UG-11P forms):
I Accommodation and food service activities
I 55 – Accommodation
I 56 – Food and beverage service activities
These surveys cover enterprises and unincorporated enterprises whose principal activity is classified in Section I (NACE Rev. 2).
B) Quarterly Structural Business Survey (SBS-03 form):
This survey covers enterprises whose principal activity is classified into non-financial business economy (Sections A-S, excluding K and O). For the purpose of production of services turnover indices, relevant sections and divisions are considered, except I.
H 49 – Land transport and transport via pipelines
H 50 – Water transport
H 51 – Air transport
H 52 – Warehousing and support activities for transportation
H 53 – Postal and courier activities
J 58 – Publishing activities
J 59 – Motion picture, video and television programme production, sound recording and music publishing activities
J 60 – Programming and broadcasting activities
J 61 – Telecommunications
J 62 – Computer programming, consultancy and related activities
J 63 – Information service activities
L 68 – Real estate activities
M 69 – Legal and accounting services
M 702 – Management consulting services
M 71 – Architectural and engineering activities; technical testing and analysis
M 73 – Advertising and market research
M 74 – Other professional, scientific and technical activities
N 77 – Rental and leasing activities
N 78 – Employment activities
N 79 – Travel agency, tour operator reservation service and related activities
N 80 – Security and investigation activities
N 81 – Services to buildings and landscape activities
N 82 – Office administrative, office support and other business support activities

Level of data processing: divisions-level (2-digit), European level for dissemination M 70.2 are estimated on the basis of the turnover estimates on the level of M 70 and the corresponding structures of turnover from sampling frame (auxiliary variable).
At higher level of aggregation, turnover indices have been prepared for:
Services – total;
H – Transportation and storage;
I – Accommodation and food service activities;
J – Information and communication;
L – Real estate activities;
M – Professional, scientific and technical activities, and
N – Administrative and support service activities.
Administrative data source - VAT returns obtained from the Tax Administration are used in order to provide data on turnover for unincorporated enterprises from all covered sections excluding Section I.
There is no threshold by size of businesses (according to the number of employees) - all size classes are covered by the surveys and administrative data source.

The objective of the turnover index is to show the development of the market for goods and services.

Turnover comprises the totals invoiced by the observation unit during the reference period, and this corresponds to market sales of goods or services supplied to third parties.  Turnover includes all costs charged to the customers (transportation, packaging, insurance, etc.) even when those costs are shown separately in the invoice. Turnover excludes rebate, discount, cash accounts, excise, VAT and other taxes which are calculated at the time of products sales.

Statistical observation unit and a reporting unit is an enterprise.
Administrative data source - VAT returns obtained from the Tax Administration are used in order to provide data on turnover from unincorporated enterprises and annual financial statements.

The target population consists of enterprises with main economic activity is one of the NACE activities listed under item 3.3.
The sampling frames for statistical surveys are constructed using the frozen version of Statistical Business Register (SBR) from 31st of December of the year t-1, where t is the current year. The sampling frames were constructed from these lists of enterprises by excluding the smallest enterprises. Annual turnover and size of enterprises are taken from financial statements for the year t-2, where t is the current year.

The surveys listed under item 3.1 use different criteria to exclude the smallest units from the sampling frames with respect to turnover from the balance sheet:

A) I: Enterprise is excluded if its turnover is less or equal than 2500 thousand RSD; Unincorporated enterprise is excluded if its turnover is less or equal than 1 thousand RSD;
B) In other NACE Rev.2 Services activities: The percentage of excluded turnover is less or equal to 4%, by NACE divisions.

Tax Administration Data Base (monthly and quarterly) is an additional source on turnover for unincorporated enterprises which are not covered by statistical surveys. Turnover data of about 7.6 thousand units from Tax administration is added to the survey estimates of turnover.
For statistical surveys, the number of enterprises/ unincorporated enterprises in the SBR population and the sampling frame in Services NACE Rev. 2 activities are presented in the Table below.

Table 1. Number of units in statistical surveys for Services in 2022

The reference area is the Republic of Serbia.

Remark: Starting from 1999 the Statistical Office of the Republic of Serbia has not at disposal and may not provide available certain data relative to AP Kosovo and Metohia and therefore these data are not included in the coverage for the Republic of Serbia (total).

The turnover of the units located outside the Serbian territory is not included.

For all data series, data are available from the first quarter of 2008 onwards.

Base year: 2015 = 100

Indices (2015 = 100) are unadjusted, calendar adjusted and seasonally adjusted.

Reference period is calendar quarter.

National level: 

The official statistics law (Official Gazette RS, No 104/09): 

http://www.stat.gov.rs/media/2322/zakon_o_statisticie.pdf

Decision of  the Programme of Official Statistics over the period 2021 – 2025 (Official Gazette RS, No 24/21)

https://www.stat.gov.rs/en-US/o-nama/dokumenti

Regulation on the Plan of official statistics for 2022 (Official Gazette of the RS, No. 133/21) 

https://www.stat.gov.rs/media/358293/planzvanicnestatistike2022en.pdf

Law on the Classification of activities (Official Gazette RS, No 104/09):

http://www.stat.gov.rs/media/2319/zakon-o-klasifikaciji-delatnosti.doc

European level:

Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics, repealing 10 legal acts in the field of business statistics (EBS-Regulation);

Commission Implementing Regulation 2020/1197 laying down technical specifications and arrangements pursuant to Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics repealing 10 legal acts in the field of business statistic (General Implementing Act);

STS data requirements overview June 2021.

Considering that SORS has Transitional arrangements for the implementation of the new Regulation on European Business Statistics (European Business Statistics Regulation ─ EBS), it has been partially implemented, but the current legal basis for STS indicators has also been applied: Council Regulation no. 1165/98 of May 19, 1998 on short-term statistics and subsequent amendments.

There is no data sharing to other international institutions.

At the national level data confidentiality is stipulated by:

Official Statistics Law (Official Gazette of RS, number 104/2009), Articles 44, 45, 46, 47, 48, and 49.

http://www.stat.gov.rs/media/2322/zakon_o_statisticie.pdf

Rulebook on statistical data protection in the Statistical Office of the Republic of Serbia

http://www.stat.gov.rs/media/2343/rulebook-on-statistical-data-protection-in-sors.doc

Guidelines on measures of data and information protection in the Statistical Office of the Republic of Serbia

http://www.stat.gov.rs/media/2341/guidelines-on-measures-of-data-and-information-protection-in-the-sors.doc

European level:

Regulation (EC) No 223/2009 of the European Parliament and of the Council of 11 March 2009 on European statistics.

Confidential data are treated according to Official Statistics Law and Rulebook on Statistical Data Protection in the SORS of the RS, article 3. "Confidential statistical data, in terms of this Rulebook, are individual data as well as aggregates based on which the data holder may be in whatever way recognized", article 11"Confidential data from Article 3 of this Rulebook are considered official secret and cannot be published or communicated, that is, they cannot be part of aggregated data from which individual data can be identified".

Data are published on the level at which they are not confidential. 

A) Calendar of releases is available at SORS website on the 1st day of December every year for the forthcoming year: 

http://www.stat.gov.rs/en-US/calendar. 

B) Not available.

A) Calendar of releases is available at SORS website: http://www.stat.gov.rs/en-us/calendar/

B) Not available.

The data obtained through statistical surveys are released at the:

- internet presentation: http://www.stat.gov.rs/en-US/,

- in the database: http://data.stat.gov.rs/?caller=SDDB&languageCode=en-US,

- in statistical publications: http://www.stat.gov.rs/en-US/publikacije/.

The results of official statistics are available at the same time to all users on impartial basis; any privileged access by external users before their release is not allowed.

The frequency of dissemination is quarterly.

Not available.

A) Data on Section I are published in the Monthly statistical bulletin, Statistical Yearbook of the Republic of Serbia and Statistical Pocketbook of the Republic of Serbia.

B) Not available.

A) Data on Section I is available in the Statistical Database on

http://data.stat.gov.rs/Home/Result/220101?languageCode=en-US&displayMode=table and

http://data.stat.gov.rs/Home/Result/220102?languageCode=en-US&displayMode=table

B) Turnover indices in services are available on SORS Statistical database on   

http://data.stat.gov.rs/Home/Result/290102?languageCode=en-US&displayMode=table

On request, the access to anonymized microdata is ensured to scientific and research institutions. The request can be placed by email at stat@stat.gov.rs, or by regular mail addressed at 5 Milana Rakića St, Belgrade.

For more information, please see http://www.stat.gov.rs/en-US/korisnicka-podrska/micropodaci.

Quarterly indices of Turnover in Services (unadjusted, calendar-adjusted and seasonally adjusted), starting from the first quarter of 2008, are submitted to Eurostat in accordance with the required level of detail, within the specified deadlines and in the required format.

A)  Questionnaires for Accommodation and food services turnover are available on SORS website:

http://www.stat.gov.rs/istrazivanja/methodology-and-documents/?a=22&s=0

Methodological explanations (metadata) are available at SORS website:

http://data.stat.gov.rs/Home/Result/220102?languageCode=en-US

B) Content of the Quarterly structural business survey form is available on the SORS website:

http://www.stat.gov.rs/en-US/istrazivanja/methodology-and-documents/?a=19&s=1904

Methodological explanations for turnover in services are available within on SORS Statistical database:

http://data.stat.gov.rs/Home/Result/290102?languageCode=en-US

Not available.

The SORS quality management system is relied on the Serbian official statistics mission and vision, as well as on the European Statistics Code of Practice – CoP and the Total Quality Management – TQM principles, which together make the common quality framework of the European Statistical System (ESS).

For more information, please see the documents at: http://www.stat.gov.rs/en-US/o-nama/sistem-upravljanja-kvalitetom.

Through all phases of data production, main quality aspects are controlled by statisticians, sample methodologist and IT experts. 

The main users of these data include State authorities, financial institutions, economic analysts, media, researches and students, enterprises, internal users (National Accounts Department) and Eurostat.

On biennial basis (once in two years), by the means of web interview, implemented is the User Satisfaction Survey. The survey results are available at SORS website: http://www.stat.gov.rs/en-US/o-nama/sistem-upravljanja-kvalitetom.

In particular User’s satisfaction survey which refers to STS indicators, not yet conducted.

A) Indicators are harmonized with the concepts and definitions in methodology based on the EU Council Regulation (EU) 2019/2152 of the European Parliament and of the Council on European business statistics. Comparable data series could be recalculated from the earlier time periods, but for consistency services overall, the indices are prepared from the first quarter of 2008.

B) Indicators are mostly harmonized with the concepts and definitions in methodology based on the EU Council Regulation EU) 2019/2152 of the European Parliament and of the Council on European business statistics. The requirements on the length of the time series are not fulfilled. The reasons are as follows:

Quarterly Structural Business Survey was introduced into the statistical system as a regular survey in 2008. In Serbia, implementation of the National Classification of Activities (CA 2010), which corresponds to NACE Rev. 2, started from the first quarter 2011. For recalculation of data for previous periods, micro approach was applied: data for previous periods were calculated by assigning a new activity code to each statistical unit and repeating the estimation procedure. Since NACE REV. 2 is characterized by regrouping of activities in services sections and with introduction of new sections that have not previously existed, there were not enough auxiliary inputs to provide data for backcasting of sufficient quality. Therefore, the first quarter 2008 is a starting point of the time series.

In order to backcast turnover by domains of ANNEX D for unincorporated enterprises for the period 2008-2011 (using Tax Office data bases), it was assumed that the dynamics of unincorporated enterprises operations follow the dynamics of companies operations. The computations were as following:

For each of the quarter in the period 2011-2014, a ratio of unincorporated enterprises’ turnover and enterprises turnover was calculated, according to tax data. These ratios represented measures of size of the unincorporated enterprises’ turnover with respect to the enterprises turnover; ratios were average across years, by quarters and domains. Finally, the turnover of unincorporated enterprises, by quarters and domains, was estimated by multiplying the averaged ratios with the corresponding estimates of turnover from the SBS-03 survey.

Data on turnover in services are collected in statistical surveys or are derived on the basis VAT returns, obtained from the Tax Administration. Consequently, the results have sampling and non-sampling errors, of which the main are: coverage, nonresponse, measurement, and processing error.

The design and organization of the surveys, as well as the data collection and processing methods ensure sufficient overall accuracy.

Tax administration data is available 40 days after the reference month (quarter). For units that report VAT data on a monthly basis, quarterly values of turnover are obtained by summing the monthly values. The quarterly turnover estimates in services are calculated by summing units’ quarterly turnover values; for units that report VAT data on a quarterly basis, monthly values for the three months of the quarter are estimated.

The sampling designs of the statistical surveys ensure results of satisfactory precision for the estimates of totals required by Eurostat.
The sampling weights are corrected for non-response and for the presence of outliers.
Coefficients of variation are calculated for estimates of turnover totals by NACE Rev. 2 divisions and groups that are in the coverage of Services Turnover, as well as for corresponding sections and the Republic of Serbia. On the level of the Republic of Serbia, for 2022 quarters, coefficients of variation are about 2.1%.
Quarterly average of the coefficients of variation is highest in divisions N 78 (16.6%), N 79 (14%) and M 71 (13.7%). Quarterly average of the coefficients of variation is lowest in divisions J 62 (3.2%) and H 51 (4.1%).
The response rate is high in all quarters. On the level of the Republic of Serbia, the rate is between 85.2% (fourth quarter) and 86.4% (third quarter).

The main non-sampling errors in the results on the turnover in services are coverage, non-response, measurement, and processing errors.
Frame imperfection is the major cause of coverage errors. SBR variables: an economic activity of the enterprise, registration status and turnover from the financial statement for the year t-2 are of crucial importance for the definition of the surveys sample designs and sample selection. If these variable values are not updated, or with an error, then coverage errors may occur.
In addition, the under-coverage errors arise because the frame lists contain only the data on enterprises that have submitted the financial statements for the year t-2. Those that opened after that year are not covered unless it is known that they are exceptionally big or important for the activity they perform. Under-coverage errors are caused also by exclusion the smallest enterprises from the sampling frame with respect to turnover (from financial statements for the year t-2).
Although the under-coverage error is not measured, it is assumed that it does not significantly affect the results because the survey does not include primarily small enterprises.
Over-coverage and non-response errors (or response rates) are calculated using information about the response of the unit.
The units of over-coverage are those for which the response is: closed, extinguished; blocked, not working; outside the scope of the survey (does not perform the selected activity); bankruptcy and liquidation.
Based on the results for 2022, the over-coverage rate for the Republic of Serbia is in the range of 3.4% (first quarter) to 6.2% (fourth quarter).
Units are classified as non-response if the response is: runs a business, but refuses to submit a report; not found or moved (undeliverable questionnaire) and other reasons (unknown reason of non-response).On the opposite, all other in-scope units are classified as the response. These are the units that, at the data collection phase, have provided data. Based on the results for 2022, the response rate for the Republic of Serbia is in the range of 85.2% in the fourth quarter to 86.4% in the third quarter. The size-weighted response rate is in the range of 88.2% in the second quarter to 91.5% in the third quarters. As a measure of size the turnover from sampling frame (auxiliary variable) is used.
In order to reduce the non-response, the following measures are undertaken: web questionnaire is introduced, reminders are sent in written or e-mail form, reporting units are contacted by telephone. Once a year, a new coordinated sample with rotation is selected (using the SORS system of coordination). In this way, a gradual replacement of small sampling units is provided, among which non-response is frequent. Every effort is made to reduce non-sampling errors to a minimum.
In order to reduce non-sampling errors caused by human errors, the following measures are undertaken: collected data are entered in the PC application that represents the so-called "controlled entry". During this phase, the program does not allow the entry of numerically inconsistent data. The next step is to run the program for checking logical inconsistencies. Further steps in data editing are based on the analysis of statistical experts and resulting with correction of discovered errors. If necessary, the reporting unit is contacted in order to get the correct data. Finally, data validation is realized during analysis of the aggregates.
In the survey SBS-03, data imputation is carried out for non-responding units whose non-response could significantly increase the bias of the results. These are, above all, extremely large units in their field of activity or those that are specific in some of their characteristics. The imputation method is constantly evolving, and for auxiliary variables, various sources of data are used such as tax information, final accounts, and survey data.
Based on preliminary results for SBS-03 and referring only to Services excluding section I, the imputation rate for the Republic of Serbia is in the range of 0.09% (third quarter) to 0.67% (fourth quarter).

A) The results of surveys are available 60 days after the end of the reference quarter. 

B) The first results are available 55 days after the end of the reference quarter and placed at the disposition internally to Quarterly National Accounts unit. Provisional data is disseminated to Eurostat 60 days after the end of the reference quarter. 

A) There is no time lag between the actual delivery of the data and the target date when it should have been delivered. Deadlines are respected and data are published and delivered on time, according to the pre-announced publications calendar.

B) Turnover indices in services are published in the dissemination database 60 days after the end of the reporting quarter. The data are transmitted to Eurostat in the required deadlines and technical format.

Turnover indices in services are representative only for level of Serbia – total. They are not representative for the lower regional levels.

The data series are comparable in time.

The data obtained by all three statistical surveys (Quarterly Surveys on Catering Trade and Quarterly Structural Business Survey) are used as an input data for the calculation of the quarterly macroeconomic aggregates. It means that the degree of their compliance is the highest possible.

The data from quarterly surveys and annual SBS are not completely coherent. The reasons are the different purposes and hence different used methods for the statistics. There are also some differences in the European definitions. 

The data from statistical survey are checked for internal coherence. Each level of aggregated data is compiled directly from micro data. Control is also done by comparing the value of turnover from Quarterly Structural Business Survey with corresponding data from the Department of Statistics of Trade, Catering and Tourism; with annual financial statements and with monthly and quarterly data from Tax Administration.

Standardized information on cost and burden is not systematically collected.

A system of coordination of random samples of business systems has been introduced, which reduces the burden of small units.

More details in publication "Sample coordination of statistical business surveys":

http://publikacije.stat.gov.rs/G2014/PdfE/G201410089.pdf

The SORS general revision policy constitutes the global frame ensuring that each statistical domain shall define its own revision policy in compliance with its specific nature.

The general SORS revision policy determines:

- general rules of revisions of the published data,

- forms of informing users as regards the possible causes of revisions,

- categories of revisions, and

- documents covering all aspects of revisions.

The general SORS revision policy is available at SORS website:

http://www.stat.gov.rs/media/2332/general-revision-policy.docx

The same revision policy is applied for publishing of national data and for data transmitted to Eurostat.

So far, thе national calendar revision does not exist. 

The benchmarking of turnover data from the Quarterly Structural Survey and data from the Quarterly Survey of Catering is regularly conducted. Also, comparisons are made with monthly and quarterly data from the Tax Administration database, as well as with annual financial reports.

A) Turnover indices for Section I of NACE Rev. 2 are considered as final. If errors are detected, corrected data are published and disseminated as soon as possible. Major revisions are due to changes in the methodology, classification of activities (e.g. the implementation of NACE Rev. 2) and base year change. Routine revisions of Accommodation and food services (Section I of NACE Rev. 2) data are due to new or corrected data received from reporting units or administrative sources. The corrected data are published together with the previous data in the following quarter with an appropriate explanation. All published monthly indices are treated as the previous, which means that some corrections are possible based on subsequently obtained information.

B) Turnover indices in other Services activities (excluding Section I) for all quarters of the current year are considered as provisional till the end of October next year. At that time, additional data such as annual financial statements, complete Tax Administration Data Base are at disposal. These data are used to check, benchmark and detect errors in survey data.  Estimates are recalculated, with corrected data and with included data of enterprises that were received after the quarter deadline. These revised data, are the final and are available to the users in the SORS database the last day of October next year: http://data.stat.gov.rs/Home/Result/290102?languageCode=en-US.

The final data are sent to the EU last day of November, together with data of the 3rd quarter of the current year.

The major revision was carried out in 2011 when the implementation of the National Classification of Activities (CA 2010), which corresponds to NACE Rev. 2, started. Since NACE REV. 2 is characterized by the regrouping of activities in services sections and with introduction of new sections that have not previously existed, direct comparison of the entire CA (2010) and the previous CA (1996) was not possible. For recalculation of estimates for previous periods, a micro approach was applied. Based on correspondence matrices of old and new economic activity, to each sampling unit from previous periods, the new activity code was assigned. Estimation procedure was repeated using new activity codes. Therefore, the 2008-2011 indices are considered as estimated.

The rebasing from 2010 = 100 to 2015 = 100 has been made.

Routine revisions will be promptly implemented.

The data obtained by all four quarterly surveys are used as an input data for the calculation of the quarterly macroeconomic aggregates. It means that benchmarking is carried out within the Units of Quarterly National Accounts.

The data from quarterly surveys and annual SBS are not completely coherent. The reasons are the different purposes and hence different used methods for the statistics. There are also some differences in the European definitions. However, the Annual Structural Statistics Unit carried out benchmarking at microdata level with Quarterly Structural Business Survey, nine months after the reference year.

Mean Revision (MR) and Mean Absolute Revision (MAR) are used as revision indicators. 

They are calculated on year-on-year growth rates for original and calendar adjusted data. The calculated values for the period first quarter 2018 - fourth quarter 2022 for Services Turnover index – total are:

• Turnover indices in service – total, original data series: MR = - 0.79;  MAR = 1.03 and

• Turnover indices in service – total, for calendar adjusted series: MR = 0.02; MAR = 0.18.

The source of data for calculation of Turnover in Services, are statistical surveys and administrative data (VAT returns obtained from the Tax Administration).

Surveys are based on random samples. The sampling design of these surveys is stratified random sample. Specific characteristics of the samples are:

A) Quarterly Survey on Catering Trade for Enterprises (UG-11):
The sampling frame units are stratified according to NACE Rev. 2 divisions, NSTJ 2 (National NUTS 2 territorial classification) and an indicator of census strata. Census strata are strata that contain units that have significant turnover according financial statement.
    Quarterly Survey on Catering Trades for Unincorporated enterprises (UG-11P):
The stratification of the sampling frame is according to indicator of TAX payer, size and NSTJ 2 territorial classification. Four size classes are determined with respect to the values of turnover from financial reports. The largest units form the size class whose units are completely enumerated. Other three size classes are of equal size.

B) Quarterly Structural Business Survey:
The sampling frame units are stratified according to NACE Rev. 2 divisions, two classes according to the number of employees (less than 50 employees and 50 and more) and two classes according to turnover (census, and non-census). Census strata are strata that contain the largest units, with respect to turnover.
Auxiliary variable values on turnover are from financial statements, while the number of employees is a twelve month average on the number of employees who have an employment contract (definite or indefinite). The source for employees is The Central Register of Compulsory Social Insurance (CRCSI), data that is available at the time of the construction of the frozen version of SPR of December of the year t-1.
Remark: To fulfil national requirements, a more detailed stratification of the frame was defined so that the activities in the coverage of the Information and Communication Sector are planned domains. In these domains, higher precision was set for the estimates of auxiliary variables totals.

In all surveys, sample allocation of units is made according to Bethel algorithm, which is based on a Neyman`s allocation method. The overall sample size and the allocation among the different strata is determined starting from the constraints imposed in the survey on the accuracy (i.e. planned errors in terms of coefficients of variation) of the estimates of interest or in this case on auxiliary variables (turnover/number of employees) by main survey estimation domains.
Samples are selected using sequential sampling scheme based on permanent random numbers from the uniform distribution on (0,1). This method of selection, with the rotation of sampling units, is a part of SORS system of coordination that is based on the SAMU system (SAMU, 2003). See Sample Coordination оf Statistical Business Surveys.

Table below includes data on sample sizes, sample fractions and net samples by surveys.

Table 2. Sample size, sample fraction and net sample size for the year 2022

Note: For calculation of final results for Other Services (excluding I), the net sample size will be larger.

In statistical surveys, data are collected quarterly. Tax administration data are at disposal: monthly (for large taxpayers) about 40 calendar days after the end of the month and quarterly (for small taxpayers) 40 days after the end of quarter.

In surveys, the method of collection is by post, by e-mails or by Web application. Questionnaires are sent to reporting units before the expiration of the referent quarter. Questionnaires are also available on the SORS Website. Alternatively, questionnaires are collected using fax machines.

For unincorporated enterprises, data from VAT declarations are used. Data is downloaded via FTP (File Transfer Protocol) server.

Actions taken to speed up or increase the rate of response are urgency letters by post, telephone contacts, and e-mails.

For all surveys, data validation is carried out through the chain of activities: control of collected questionnaires by regional statistical staff; data entry into the PC by an interactive application which does not permit some crucial errors; detailed checking and correction of data in the program for batch editing; data editing during the analysis of data and the estimation procedure; data validation during analysis of the aggregates. If necessary, reporting units are contacted in order to get correct data.

The methods used to treat non-response: imputation for large non-respondents or those with some specific characteristics (Services activities other than I); the other units are treated by reweighting (weights are adjusted to take account of non-response).
The standard estimation procedure for the stratified simple random sample is used. Estimates of totals are calculated by summing the weighted sampling values. The sampling weight is equal to the ratio of the number of units in the stratum to the number of stratum units in the sample. It is adjusted for non-response. Also, enterprises that are marked as outliers are extracted into special census strata. The weights for the remaining units of a stratum from which an outlier originated are corrected.
The service indices are compiled as simple indices (value relative). The indices are calculated directly from the data.

More information about metadata calendar and seasonal adjustment is in the Annex.

No comment.