Quarterly indicators of business activities of enterprises

Statistical Office of the Republic of Serbia (SORS)

Structural business statistics Unit

Gordana Zamaklar

Statistician methodologist for Quarterly Structural Business Statistics

5 Milana Rakića, Belgrade

gordana.zamaklar@stat.gov.rs

(+381) 11 2412 922/ 352 ext

Quarterly Structural Business Survey (SBS-03 form) provides data on financial operations of enterprises which is based on: operating income, operating costs, stocks enterprises as well as on the changes in the structure of economic activities in the non-financial business economy. The results of this survey are presented with appropriate indexes on quarterly (current quarter / previous quarter) and annual level (current quarter / same quarter of the previous year). This survey was first conducted in 2007 as a pilot survey, and in 2008 it was introduced into the Statistical System as a regular survey.

The National classification of Activities - CA, 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 coverage of the survey is a set of economically active units engaged in the production and sale of market-oriented goods and services, i.e. units that are classified into the non-financial business economy according to their operating. The non-financial business economy does not cover sections K (Financial and insurance activities) and О (Public administration and defence; compulsory social security) CA (2010).

Even though, according to international standards, the non-financial business economy does not cover the sections А (Agriculture, forestry and fishing), P (Education), Q (Human health and social work activities), R (Arts, entertainment and recreation) and S (Оther service activities) CA (2010), this survey includes the market part of the listed sections, i.e. all enterprises and other legal entities (all business entities) which revenues from sale of goods, products and services exceed 50% of the operating income.

Entrepreneurs are excluded.

The reporting units are all economically active enterprises and other legal entities that, pursuant to the Law on the Classification of Activities (“Official Journal of RS”, No 104/09) and Regulation on the Classification of Activities (“Official Journal of RS”, No 54/09), are classified into the following sections:

А     Agriculture, forestry and fishing

В     Mining and quarrying

C     Manufacturing

D     Electricity, gas, steam and air conditioning supply

Е     Water supply; sewerage, waste management and remediation activities

F     Construction

G    Wholesale and retail trade; repair of motor vehicles and motorcycles

H     Transportation and storage

I      Accommodation and food service activities

J     Information and communication

L     Real estate activities

М    Professional, scientific and technical activities

N     Administrative and support service activities

P     Education

Q    Human health and social work activities

R     Arts, entertainment and recreation

S     Оther service activities

The main statistical unit in structural business statistics is a business entity. In this survey, business entities are classified according to the principal (main) activity of an enterprise.

Level of data processing: level of CA Division (two-digit level).

According to the international definition (EUROST, OECD), the Information and Communication Sector, as a separate aggregate, consists of the following activities according to the (NACE Rev.2):

ICT sector - Manufacturing

26.1     Manufacture of electronic components and boards

26.2     Manufacture of computers and peripheral equipment

26.3     Manufacture of communication equipment

26.4     Manufacture of consumer electronics

26.8     Manufacture of magnetic and optical media

ICT sector - Services

46.5     Wholesale of information and communication equipment

58.2     Software publishing

61        Telecommunication

62        Computer programming, consultancy and related activities

63.1     Data processing, hosting and related activities; web portals

95.1     Repair of computers and communication equipment

The main objective of the survey is to obtain data on quarterly dynamics of financial operations of enterprises as well as on the changes in the structure of economic activities in the non-financial business economy. Financial operations of enterprises are based on data on operating income, operating costs and stocks. In accordance with the main objective of the survey, appropriate indices are presented on a quarterly (current quarter / previous quarter) and annual level (current quarter / same quarter of the previous year).

Operating income represents the results of business operations of a business entity, expressed in monetary value. It always refers to a certain period (month, quarter, year). It covers: revenues from sale of goods, products and services; revenues from capitalized production; revenues from premiums, subsidies, donations, recourse, etc., and other operating income (from rentals, memberships, royalties and license fees and other operating revenues). VAT is excluded.

Revenues from sale (turnover) represent the value of revenues of goods, finished products and services delivered realised on the domestic and foreign market.

Revenues from capitalized production represent the value realised by capitalized production of consumption of goods, products and services for own purposes.

Revenues from premiums, subsidies, donations and recourse, etc. represent the value realised by a business entity from premiums, subsidies, donations and recourse, tax refund and based on conditioned donations.

Other operating income represents the value realised by the business entity from rentals (land, machinery, transport equipment, inventory, etc.), from memberships (from business associations and other memberships), from royalties and license fees (based on: patents, trademarks, copyrights and other rights).

Operating costs represent the costs of business operations, expressed in monetary value. They always refer to a certain period (month, quarter, year). They cover: purchase value of goods sold; raw materials and energy costs; costs of salaries, remuneration and other personnel costs; costs of industrial services; costs of non-industrial services, excluding taxes and social contributions.

Purchase value of goods sold represents the value of goods and real estate purchased for resale.

Raw materials and energy costs represent the value spent on the purchase of raw materials for the manufacture of raw materials, direct and indirect materials; materials overhead, fuels and energy and spare parts.

Costs of salaries, remuneration and other personnel costs represent the value spent on salaries, remunerations, taxes and contributions payable by the employer; remunerations to third parties that are not employed (service contracts, temporary and occasional works contracts, etc.), remunerations for the director, i.e. members of steering and supervisory bodies, as well as other personal expenses and compensations (severance payments, jubilees, daily allowances for business trips, allowances for fieldwork, etc.).

Costs of industrial services represent the value spent on the production of services, such as: output, transport services, maintenance, costs of rentals, fairs, advertisement and propaganda, researches, etc. 

Costs of non-industrial services (excluding taxes and social contributions) represent the following values: value of non-industrial services (health, legal, cleaning, accountancy, counseling, security, personnel’s professional training, etc.); the value of costs of representation, insurance premiums (for fixed assets, stocks, production, employees); the value of payment  operations and memberships (bank commissions and other charges; bank guarantee services fees, bank loan services fees, etc.) and the value of membership costs; the value of taxes and contributions.

Stocks are a form of working assets. Their value is the monetary value on a given day (i.e. situation on the first and last day of the reference quarter). They include: raw materials, work in progress, finished products and goods.

Raw materials stocks represent the value of accounted purchases of raw materials (raw materials and basic materials, auxiliary materials, other materials, fuels and lubricants, materials being processed, finished off and handled, packaging write-off); spare parts and tools and inventories.

Work in progress stocks represent the value of work in progress and services in progress.

Finished products stocks represent the value of finished products and finished services.

Goods stocks represent the value of the accounted value of goods purchased; goods in warehouses, depots and stores with other legal entities; goods in retail trade; goods being processed, finished off and handled; goods in transit and on the road.

Number of employees (quarterly average) represents the number of persons who work in an enterprise, have a work contract for a definite or indefinite time and are paid for their work.

The number of employees includes all persons on payroll, including home workers, apprentices, paid working proprietors and paid family working, those on temporary leave, part-time employees. Included are also persons who have a contract for occasional and temporary work with an employer (including also those engaged through youth’s and students’ agencies). 

Excluded are unpaid working proprietors and family members, persons on the basis of a temporary work contract, temporary agency workers, workers with a temporary service contract, members of the management board and supervisory board (those not having the status of employee), as well as persons on long-term leave (long-term sick leave, military service, etc.).

Statistical observation unit and a reporting unit is an enterprise.

The target population consists of enterprises with main economic activity is one of the NACE activities listed under item 3.3 of this document.

The sampling frame is constructed using the frozen version of the Statistical Business Register (SBR) from the 31^st of December of the year t-1, where t is the reference year. The 5% smallest enterprises with respect to turnover from the financial statement for the year t-2 are excluded from the sampling frame.

The number of enterprises in the population and the sampling frame is presented in the Table below.

Table 1. Number of units in the population and in the sampling frame, 2023.

Republic of Serbia

^1]) Covers: mining and quarrying; manufacturing; electricity, gas, steam and conditioning supply; water supply, sewerage, waste management and remediation activities and construction.

²⁾ Covers: real estate activities; professional, scientific and technical activities; administrative and support service activities; education, human health, and social work activities; arts, entertainment and recreation and other service activities.

The indices are calculated in current prices, and they refer to 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).)

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

With respect the main objective of the survey, appropriate indices are calculated on quarterly (current quarter / previous quarter) and annual level (current quarter / same quarter of the previous year).

Indices are presented in current prices and an unadjusted form (current quarter / previous quarter and current quarter / same quarter of the previous year).

Reference period is calendar quarter.

Conducting Quarterly Structural Business Survey is based on the following legal acts of the Republic of Serbia:   

─ 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 2023 (Official Gazette of the RS, No. 141/22) 

https://www.stat.gov.rs/media/377224/planzvanicnestatistike2023_engleski.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:

European Business Statistics (EBS) Regulation (EU) 2019/2152 of the European Parliament and of the Council and Commission Implementing Regulation 2020/1197 laying down technical specifications and arrangements pursuant to the mentioned EBS Regulation (General Implementing Act).

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. 

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. All SORS releases are launched at 12.00. Any divergence from the defined time schedule are announced in advance and explained in the Calendar. 

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

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 releases and 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.

The indices of operating income and costs in non-financial business economy have been published in the regular statistical release “Quarterly Structural Business Survey” (preliminary data), since 2009. 

http://www.stat.gov.rs/en-us/oblasti/strukturne-poslovne-statistike/kvartalna-dinamika-poslovanja-privrednih-drustava/

In the period 2007-2016 the final data were published in the edition "Working Documents", on annual basis.

https://www.stat.gov.rs/publikacije/publication/?p=9760

From 2017, the final data are available in SORS Statistical database:

http://data.stat.gov.rs/Home/Result/190402?languageCode=en-US

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

Not available.

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

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. 

The overall quality of survey data is extremely good. Through all phases of data production, the main quality aspects are controlled by statisticians, sample experts and information technology experts.

The data obtained by means of this survey are used to calculate quarterly macroeconomic aggregates. Furthermore, these data can also be used for the following purposes: current monitoring and study of trends in the non-financial business economy; current analysis of the effects of economic policy measures on the non-financial business economy; study of the development and structural changes in the non-financial business economy, particularly in business services as well as the fulfillment of the requirements towards international organisations concerning short-term indicators on the turnover of business services.

The users of those data are: government bodies, chambers of commerce, scientific institutes and other organisations studying and analyzing short-term trends in the business economy, as well as enterprises and other individual users of data. The main internal user of those data is the Department of national accounts.

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.

The results of the survey are used primarily for the calculation of quarterly macroeconomic aggregates and are completely harmonized with the requirements of internal users. In order to fulfil obligations to the European Statistics Office (EUROSTAT) in the part of short-term indicators on Services Turnover, part of the results of this survey is used to calculate the turnover indices in the coverage of business services (sectors G to N, indicator D-120). More details on this in the methodological explanations "Indices of turnover in service activities in the Republic of Serbia":

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

The survey is based on a random sample so that sampling error is present in the results. The main non-sampling errors are: coverage, non-response, measurement, and processing error. 

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

Preliminary estimates are disseminated 65 days after the reference quarter, while the final estimates are disseminated by the end of October of the following year. At that time, as auxiliary data, available are financial accounts for the year t as well as additional survey data which were collected after the dissemination of preliminary results. During the calculation of the final results, the complete process of estimation is repeated for all quarters.

The SBS03 sampling design ensures results of satisfactory precision for the estimates of totals by main estimation domains (Statistical release, National accounts, and international requirements).

The sampling weight is corrected for non-response and the presence of outliers. Changes in economic activity that are registered during the data collection phase are used for domain estimation. Imputation error, as a component of the estimated variance, is not calculated.

Coefficients of variation of estimates of totals (operating income, turnover, operating expenses, and other parameters) are calculated for main estimation domains. For final results for 2023, on the level of the Republic of Serbia, estimates of coefficients of variation of quarterly estimates of operating income and expenses are about 1.4%.

Standard errors are estimated for annual and chain indices for operating income and expenses by sections, as defined for statistical release. They are disseminated in the statistical release only for indices of the total operating income and expenses.

For the final estimates, the standard errors of the annual indices of operating income and expenses are in the range of 1.4 to 1.7. For chain indices, these estimates are for operating income in the range 1.0 to 1.4 and for operating expenses in the range of 0.7 to 1.3.

The response rate is high; it is highest in the first quarter (88.6%) and lowest was in the fourth quarter (85.9%). The size-weighted response rate is in the range of 90.6% in the fourth quarter to 92.4% in the first quarter. As a measure of size, sampling frame auxiliary variable of turnover is used.

The main non-sampling errors in this survey are coverage, non-response, measurement, and processing errors.

Frame imperfection is the major cause of coverage errors. Of crucial importance in the definition of the sample design and sample selection are SBR variables: economic activity of the enterprise, registration status and turnover from the financial statement for the year t-2. 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 list is constructed of 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 and by exclusion from the sampling frame the 5% smallest enterprises 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 final results for 2023, the over-coverage rate for the Republic of Serbia is in the range of 0.8% (first quarter) to 1.4% (fourth quarter).

The units are classified as non-response if the response is: runs a business, refuses to submit a report; not found (undeliverable questionnaire) and other reasons (unknown reason of non-response).

For the final results of 2023, the non-response rates are between 11.4% (first quarter) to 14.1% (fourth quarter). The weighted non-response rate for the Republic of Serbia is in the range of 13.8% in the first quarter to 15.3% in the fourth quarter. The size-weighted non-response rate is in the range of 7.5% in the first quarter to 9.4% in the fourth quarter. As a measure of size, sampling frame auxiliary variable of turnover is used.

To reduce the non-response, the following measures are undertaken: a web-based questionnaire is introduced, written and e-mail reminders, telephone contacts with the reporting units. Once a year, a new coordinated sample with rotation is selected

(http://pod2.stat.gov.rs/ObjavljenePublikacije/G2014/pdfE/G201410089.pdf).

In this way, a gradual replacement of small sample units is provided, among which non-response is frequent. Every effort is made to reduce non-sampling errors to a minimum.

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 the release of the program for computation- logical control. Further steps in data editing are based on the analysis of statistical experts and resulting in the correction of discovered errors. If necessary, the reporting unit is contacted to get the correct data. Finally, data validation is realized during the analysis of the aggregates.

Information on the number of imputed values (item imputation)  during data editing is not available, at the moment.

Data imputation is carried out for non-responding units whose non-response could significantly increase the bias of 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 are used such as tax information, annual financial reports, and survey data.

For final results 2023, the imputation rate is 0.5% in the first quarter, 0.9% in the second and fourth quarter, and 1.5% in the third quarter.

The timetable of the mаin stages of the survey is as follows:

• Producing the methodology up to 15 March.

• Transmission of questionnaires to regional offices up to 10 March (for the first quarter), 10 June (for the second quarter), 10 September (for the third quarter) and 10 December (for the fourth quarter).

• Reception of filled in questionnaires in regional offices up to 15 April (for the first quarter), 15 July (for the second quarter), 15 October (for the third quarter) and 15 January (for the fourth quarter of the previous year).

• Transmission of the entered materials to the head office in Belgrade up to 5 May (for the first quarter), 5 August (for the second quarter), 5 November (for the third quarter) and 5 February (for the fourth quarter of the previous year).

• Processing of the first results up to 25 May (for the first quarter), 25 August (for the second quarter), 25 November (for the third quarter) and 25 February (for the fourth quarter of the previous year).

• Producing and releasing the statistical release “Quarterly Business Structural Survey“ (preliminary data): 5 June (for the first quarter), 5 September (for the second quarter), 5 December (for the third quarter), and 5 March (for the fourth quarter of the previous year).

• Producing final data for all four quarters for the previous year and their release in the dissemination database: 31 October.

The first results are available 55 days after the end of the reference quarter and placed at the disposition internally to the Quarterly National Accounts unit. Preliminary data is disseminated to Eurostat 60 days after the end of the reference quarter. The indices of operating income and costs in the non-financial business economy have been published in the regular statistical release “Quarterly Structural Business Survey” (preliminary data), 65 days after the end of the reference quarter.

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.

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

The data series are comparable in time.

The data obtained by the Quarterly Structural Business Survey are used as 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. 

The data from the statistical survey are checked for internal coherence. Each level of aggregated data is compiled directly from microdata. 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; Department of Industry Statistics;  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 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 data transmitted to Eurostat.

So far, the national calendar revision does not exist. 

All indices of operating income and operating costs for the quarters in the current year are considered as provisional till the end of October next year. At  the time when additional information is obtained (such as annual financial statements, complete Tax Administration Data Base, additionally collected reports) these available data is check again, and detect errors are corrected. Estimates are recalculated, with corrected data and with included data of enterprises that was received after the quarter deadline. 

Major revisions were 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 the 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 data for previous periods, the 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.

Data is collected on a random sample of enterprises.

The sampling frame is constructed using the Statistical Business Register, version of the 31^st of December of the previous year. Frame list consists of data of active enterprises that have reported annual financial report for the year t-2, where t is the reference year. Turnover is the key auxiliary variable with values taken over from financial statements. Since 2017, auxiliary data on the number of employees, instead of financial accounts, is taken over from CROSO (Central Register of Compulsory Social Insurance) database (average of the number of employees with a permanent contract, based on data from the last twelve available months).

The frame enterprises cover at least 95% of turnover, by NACE Rev. 2 divisions.

The sampling frame is stratified according to the NACE classification of activities, number of employees and turnover.

Stratification according to NACE is into division A01-N82 and four sections P, Q, R and S (in all 74 strata).

Stratification of enterprises according to the number of employees is in two classes:

• with less than 50 employees and
• 50 and more employees.

Further stratification of frame units is according to the value of turnover:

• enterprises with a smaller turnover that are sampled and
• enterprises with a larger turnover that are enumerated completely.

According to the results of the Annual Structural Business Survey of enterprises (SBS01) for 2022, Serbian Oil Company is divided into nine parts. They are classified into special separate strata, depending upon their activity and the number of employees.

Final stratification is defined by cross-classifying activity with size classes according to the number of employees and turnover. In all, there are 239 strata; out of which 102 are census (7 census strata are reserved for the Oil Company parts). To fulfil national requirements, a more detailed stratification of the frame was defined so that the activities in the coverage of the ICT sector are planned domains. In these domains, higher precision was set for the estimates of auxiliary variables totals.

In this way, with the planned errors and additional request for the activities in the ICT sector, the sample of 3 456 units was allocated.

Sample allocation by strata is performed with Bethel algorithm (Bethel, 1989). Planned coefficients of variation for estimates of auxiliary variables totals (turnover and number of employees) by domains for 2023 are presented in the Table below. 

Table 2. Planned errors by domains, 2023

Republic of Serbia

The simple random sample is selected by a sequential scheme. Sample selection is from the point 0.25, as described in the working document Sample coordination of statistical business surveys https://www.stat.gov.rs/en-US/publikacije/publication/?p=10849 

The number of enterprises in the population, sampling frame and in the sample, as well and the net sample size are presented in the Table below.

Table 3. Number of units in the population, sampling frame and in the sample, and net sample size, 2023.              

Republic of Serbia

^1] Covers: mining and quarrying; manufacturing; electricity, gas, steam and conditioning supply; water supply, sewerage, waste management and remediation activities and construction.

²⁾ Covers: real estate activities; professional, scientific and technical activities; administrative and support service activities; education, human health, and social work activities; arts, entertainment and recreation and other service activities.

The net sample size is the number of units used for grossing up and tabulation. For the final results, the net sample size for the Republic of Serbia is 88.4%; for preliminary results, it was 87.1%.

Data are collected quarterly.

In Quarterly Structural Business Survey, the method of collection is postal, by mail, by fax machine and Web application. Questionnaires are sent to reporting units before the expiration of the referent quarter. Questionnaires are also available on the SORS Website.

Actions taken to speed up or increase the rate of response are: urgency letters by post, telephone contacts, and e-mails. The Statistical Office of the Republic of Serbia is in charge of the preparation and carrying out of the Quarterly Structural Business Survey (SBS-03). Organisational units that participate in the conduction of the survey are: head office in Belgrade, regional offices in Šabac, Zaječar, Leskovac, Kraljevo, Niš, Valjevo, Smederevo, Užice, Kragujevac and Novi Pazar; Department of Statistics of AP Vojvodina with divisions in Novi Sad, Zrenjanin, Pančevo, Sremska Mitrovica and Subotica, and Secretariat for Administration of Belgrade – Sector for statistics.

The head office in Belgrade undertakes the following activities: preparation of the methodology and tools for the survey; definition of the sampling frame, sample size, principles and criteria for the selection and selection of units in the sample (address book of reporting units); printing of questionnaires and other tools for the survey; transmission of the questionnaires to regional offices; control of the: coverage, accuracy and completeness of data; data processing (editing, correction, estimations based on the realized sample); make sure that the timetable is respected.

Regional organizational units, the Department of Statistics of AP Vojvodina and Secretariat for Administration of Belgrade – Sector for statistics undertake activities relative to the management of the survey on the field according to the address book of units selected in the sample; contact with reporting units and the with the head office in Belgrade when needing clarifications; collection of filled in questionnaires, visual control, control of data coverage and quality in the reports; data entry in a defined application; entry of information in the address book according to the related instructions in the address book; transmission of entered data to the head office in Belgrade.

Data validation is conducted during the chain of activities: control of collected questionnaires by regional statistical staff; data entry into the PC by an interactive application with some crucial errors not allowed; batch editing that is based on report generated by an application that implements logical rules; data editing during the data analysis and during the estimation procedure; data validation during analysis of the aggregates. If necessary, reporting units are contacted to get the correct data.

The basic characteristics of the estimation procedure used in SBS03 are:

• In the case of non-response, data is imputed for enterprises that are large or specific according to characteristics. For calculating the final results for 2023 data was imputed for about 23 enterprises. Missing data are imputed using: data on the presented turnover from the Tax Administration database - data from the tax declaration on value-added tax (PPPDV) of the current quarter; the current and previous SBS03 survey data and the financial reports of previous years. For the final estimates, annual financial reports of the corresponding year are used as well.
• The Horvitz-Thompson estimates, as for stratified simple random sample, are calculated for totals and their standard errors. The sampling weight is corrected for unit non-response. Also, units with outlier values for weighted turnover (about 17 units) are put in special census strata. At the same time, the weights of units from the initial strata are corrected.
• Transformations of census units (splitting, merging, etc.) are registered during the year. These data are used to correct the stratification, the number of frame and sample units in the strata.
• Changes in economic activity that are determined during data collection are utilized for domain estimation.
• The estimate of a chain index (current quarter / previous quarter), as well as of annual index (current quarter / the same quarter of the previous year) is simply calculated as quotients of corresponding estimates of totals. 
• The standard error of an index is estimated using  the Taylor linearization of ratio.
• The standard error of a chain index, which is calculated using estimates of totals of the same year, is estimated using the common units of successive samples.
• The standard error of an index based on estimates of totals of successive years is estimated using estimates of the totals, their variances, and correlation. The estimate of correlation is computed using the common units of the current and the previous year sample, with the stratification of the current year. This estimate of correlation is corrected by a factor that is equal to the ratio of the number of units in the common part of the samples and the number of units in the union of samples. Method of estimation is presented in more detail in the document Estimation of standard error of an index in case of coordinated samples.(http://www.stat.gov.rs/en-us/publikacije/publication/?p=10849)

Operating income and operating expenses indices are not seasonally adjusted.

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