ANNUAL QUALITY REPORT

Transcription

1 ANNUAL QUALITY REPORT FOR THE SURVEY ANNUAL STATISTICAL SURVEY ON CONSTRUCTION (GRAD/L) FOR 2015 Prepared by: Špela Kastelic Date: December /9

2 Table of Contents 0 Methodological Explanations Relevance Rate of Unavailable Statistics Accuracy Sampling Errors Sampling Error Coverage Bias Coverage Bias Non-Sampling Errors Non-Response Errors Unit Non-Response Rate Item Non-Response Rate Imputation Rate Coverage Errors Overcoverage Rate Measurement Errors Editing Rate Timeliness and Punctuality Timeliness Timeliness of the First Results Timeliness of Final Results Punctuality Punctuality of the First Results Accessibility and Clarity Accessibility Means Used for the Dissemination Clarity Results Presented Level (Detail) of Presentation Comparability Comparability over Time Length of Comparable Time Series Breaks in Time Series Geographical Comparability Comparability with Other Members of the European Statistical System Seasonal Adjustment Coherence Coherence between Provisional and Final Data Coherence between Provisional and Final Data Coherence with the Results of the Reference Survey Reference Survey Coherence with Reference Data Costs and Burdens Survey Costs of the Office Burden of Reporting Units /9

3 0 Methodological Explanations Brief Description of the Survey The annual survey on construction provides data on the value of construction put in place at the facility, regardless of whether these facilities are buildings or civil engineering works, and regardless of whether they are a new construction, reconstruction or maintenance work (investment or regular). It also provides information on the value of the organization that implements building projects, i.e. the service to mobilize financial, technical and physical resources for the construction of buildings (residential and non-residential) for subsequent sale. Since 2008, in the observation are included - in line with the Standard Classification of Activities (NACE Rev. 2) - in addition to construction companies also companies dealing with the organization of building projects. Data on the value of construction put in place in buildings or civil engineering works, are presented by the Classification of Types of Constructions (CC-SI) ( Data on construction are important in the analysis of the construction activities and are necessary, among other tasks, also to calculate the gross domestic product (GDP). Legal Basis for the Survey The legal basis for the survey are the National Statistics Act (Official Journal of RS, No. 45/95 and 9/01) and the Annual Programme of Statistical Surveys (LPSR) for 2016 (Official Journal of RS, No. 89/2015). Observation Units The annual statistical survey on construction involves companies which implemented construction works in the observed year or organized the building projects (the service to mobilize financial, technical and physical resources for the construction of residential and non-residential buildings for subsequent sale) as a prime contractor or as a researcher. The main contractor reports the required data for potential subcontractors. Coverage In determining the list of observation units the method of threshold coverage is used. The criterion of 74% coverage in the activities F Construction after Nace Rev 2 is taken into account. The survey sample includes all construction companies and companies dealing with the organization of building projects (section F - construction, activities 41, 42 and 43), whose value of income for the taxation of value added tax in the reference year reaches a certain threshold (EUR 217,500 for 2015), and the establishments engaged in construction activity or the organization of building projects which have at least 20 employees, and some other companies that perform construction work. In the GRAD/L survey are also included the so-called fictive units (units not appearing in the Slovene Business Register PRS) which had already been included in the survey in the previous year (in 2015 there were 5 fictive units) mostly units which are not legal establishments but are performing construction activity within a company that is registered outside construction activity. Key Variables Key variables of the annual statistical survey on construction are: type of investor, type of works, type of construction according to the CC-SI classification, value of construction works put in place, value of organization of building projects. 3/9

4 Key Statistics Key statistics of the annual statistical survey on construction are: the value of construction put in place by the type of investor, the value of construction put in place by the type of works put in place, the value of construction put in place by the type of construction according to the CC- SI classification. Questionnaire The questionnaire (only in Slovene) is available on the website: Methodological Explanations The methodological explanations are available on the website: 4/9

5 1 Relevance 1.1 Rate of Unavailable Statistics The rate of unavailable statistics is 0. 2 Accuracy 2.1 Sampling Errors Sampling Error The survey is carried out on the basis of a random sample, so the estimates do not contain the sampling error. 2.2 Coverage Bias Coverage Bias Explicit estimates of bias arising from the threshold of non-response and measurement errors can not be calculated because there are no adequate data from other sources. The sample does not cover the entire population, but it covers the population threshold. In view of the value of income for the taxation of value added tax in the reference year, 74% of the total population is captured. In 2013, weighting was introduced. In this way the bias due to threshold coverage was reduced. 2.3 Non-Sampling Errors Non-Response Errors Unit Non-Response Rate Table 2.2.: Unit non-response rate Number of adequate units 758 Number of non-responses 233 Non-response rate (%) Item Non-Response Rate In the phase of collecting and compiling the data the questionnaires are checked as to whether they are completed in full and item non-response is removed and examined. If not, the unit will be contacted by telephone or via and from it the missing information is obtained. In the phase of statistical processing thus all data of the units which report all the information required are entered and therefore there is no item nonresponse Imputation Rate We do not use the imputation of missing data. Thus, the imputation rate is 0. 5/9

6 2.3.2 Coverage Errors Overcoverage Rate Table 2.2: Overcoverage Rate Reference year 2015 Number of units in the Address book 901 Number of inadequate units 143 The rate of over-coverage (%) Measurement Errors Editing Rate Tabela 2.3: Editing Rate for the key variables Value of construction works put in place 6.6% value of organization of building projects 9.1% The table shows only data that were edited in the process of automatic logical control. Data that were edited before the process of logical control are not shown. 3 Timeliness and Punctuality 3.1 Timeliness Timeliness of the First Results Table 3.1:1. Timeliness of the First Results Date of publishing Time lag T Timeliness of Final Results Data published in the First Release are also final data, so the timeliness of final data equals the timeliness of the First Release. 3.2 Punctuality Punctuality of the First Results Table 3.2: Punctuality of the First Results Announced date Publishing date Difference 0 6/9

7 4 Accessibility and Clarity 4.1 Accessibility Means Used for the Dissemination Table 4.1: Means Used for Dissemination No.: Mean Used 1 Website YES (e.g. First Release, E-release) 2 Publication in the SI-STAT Data Portal YES 3 Publication in the interactive web tools NO (e.g. Interactive Statistical Atlas of Slovenia, Thematic Cartography) 4 Ad hoc prepared data for users according to their specification YES 5 Data available through telephone answering machine NO 6 General printed publications YES (e.g. Stat o book) 7 Thematic printed publications NO (e.g. Rapid Reports, Brochures) 8 External databases NO (e.g. Social Science Data Archives, Eurostat, OECD databases) 9 Statistically protected micro data NO 10 Preliminary access to data according to standard protocol NO To demonstrate the results 4 ways of expressing the results were used, which means that the rate of the methods used is 40%. 4.2 Clarity Results Presented All results are presented as absolute numbers Level (Detail) of Presentation Level data disemination are broken down by: Year The type of construction by CC-SI classification to the level of class Investor: Investor total Natural person Legal person: - Together - Public Administration - Utilities - Institutions and other non-profit organizations - Businesses and other organizations Type of construction activity: new construction extension reconstruction and conversion investment maintenance regular maintenance work 7/9

8 Standard Classification of Activities NACE Rev 2: NACE Rev 2 total F Construction other activities. 5 Comparability 5.1 Comparability over Time Length of Comparable Time Series The weighting data are published from 2010 onwards Breaks in Time Series There are no breaks in the time series. 5.2 Geographical Comparability Comparability with Other Members of the European Statistical System The data are not comparable with other members of the European Statistical System because the survey methodology was not determined by the EU. 5.3 Seasonal Adjustment The seasonal adjustment procedures in this survey are not applied. 6 Coherence 6.1 Coherence between Provisional and Final Data Coherence between Provisional and Final Data Preliminary data are not disclosed. We publish only final data. 6.2 Coherence with the Results of the Reference Survey Reference Survey In the sample of the survey GRAD/M for the reference year 2015 there are included all construction companies and companies dealing with the organization of building projects (Section F of the NACE Rev 2, activities 41, 42 and 43), whose value of income for the taxation of value added tax in 2014 reached at least EUR 966,000, and the establishments engaged in construction activity or the organization of building projects that have at least 20 employees, and some other companies that perform construction work. In the address book for the reference year 2015 there were included 227 units. The survey takes place monthly on the basis of the data obtained through questionnaires (postal survey) Coherence with Reference Data Table 6.1 shows the indices of the reported values on construction works for the surveys GRAD/M and GRAD/L in 2015, calculated to the average of The differences are 8/9

9 mainly due to the differences in the sample of these two surveys. In the sample of the GRAD/L survey more reporting units are included than in the sample of the GRAD/M survey. Since data for GRAD/L are collected for the previous year and for GRAD/M for the current year, when establishing a sample for GRAD/L all changes detected in reporting units (demographic changes, bankruptcies, etc.) in GRAD/M are taken into account. Table 6.1: Coherence with Reference Data 2015/Ø2010 GRAD/L GRAD/M Difference in index points CC_SI - TOTAL BUILDINGS CIVIL INGINEERING WORKS Costs and Burdens 7.1 Survey Costs of the Office Table 7.1: Survey costs at the Statistical Office Number of working hours spent 834 Number of reporting units that had to fill in 901 questionnaires Survey period annual Number of questionnaires per year (total) Burden of Reporting Units Table 7.2: Burden of the reporting units Number of reporting units that submitted the data 524 Annual number of questionnaires per unit 1 Time spent to fill in a questionnaire (hours) 0.5 Total time spent (hours) 262 9/9