Index of producer prices for agricultural products

Transcription

1 Statistisches Bundesamt Quality Report Index of producer prices for agricultural products Periodicity: irregular Published in For further information about this puplication please contact: Phone: +49 (0) 611 / ; Fax: +49 (0) 611 / ; Statistisches Bundesamt, Wiesbaden 2012 Reproduction and distribution, also of parts, are permitted provided that the source is mentioned.

2 Abstract 1 General information on the statistics page 3 Name of the statistics: index of producer prices of agricultural products. Survey date: calendar months. Periodicity and period for which a time series is available without any break: monthly statistics. Survey population and principle of allocating the survey units: enterprises which regularly buy and/or market agricultural products or compile associated statistics. Legal bases: Price Statistics Law. 2 Purpose and goals of the statistics page 3 Survey content: contractual prices, price-determining characteristics or average prices (in secondary surveys). Purpose of the statistics: compilation of the index of producer prices of agricultural products as an indicator of inflationary trends; for use in stable-value clauses. Major users of the statistics: European Commission, federal ministries, business associations. 3 Survey methodology page 4 Type of data collection: compulsory written survey and secondary data. Sampling procedure: written survey: purposive selection. Data collection tools and reporting channel : printed questionnaire and data derived from primary statistics. Written survey: by mail from the enterprise to the Federal Statistical Office. 4 Accuracy page 5 Overall qualitative assessment of accuracy: Index number with one decimal place; results are preliminary when published for the first time because, for some items, data are submitted later. Sampling errors: quantification not possible because no random sample. Non-sampling errors: Incorrect or inaccurate data are corrected in the context of plausibility checks. Non-response is compensated for by extrapolation, using appropriate indicators. Structural shifts in the evaluated grades of goods have an impact on the analyzed average prices. 5 Timeliness and punctuality page 6 Timeliness of preliminary results: maximum of approx. 6 weeks after the reference month. Timeliness of final results: about 15 weeks after the reference month. Punctuality: All publication deadlines are met. 6 Comparability over time and space page 6 Qualitative assessment of comparability: from 1991 data for Germany as a whole, for earlier periods only for the former territory of the Federal Republic of Germany. Changes affecting comparability over time: ensured within the base period, with restrictions across several base periods. 7 Connection with other surveys page 7 Input for other statistics: Agricultural total account as well as deflationing of values of economic statistics. 8 Other information sources page 7 Publication channels, order address: > Publikationen Thematische Veröffentlichungen Preise > Zahlen & Fakten > Datenbanken > Genesis-Online Contact information: (keyword: Agrarpreise) 2

3 1 General information on the statistics 1.1 Name of the statistics (according to EVAS) Index of producer prices of agricultural products, EVAS No.: Reference period Calendar months. 1.3 Survey date Around the middle of the reference month. 1.4 Periodicity and period for which a time series is available without any break Monthly from February Regional coverage Germany excluding the city states (Hamburg, Bremen and Berlin) because agriculture is of very little significance there. 1.6 Survey population and principle of allocating the survey units The survey population is limited in accordance with the EU-wide NACE classification (Groups 01.1, 01.2, 01.3, 01.4 and 01.5 of WZ 2008). For practical reasons, producers as such are not included in the survey population of the statistics although the index compiled represents producer prices. This is due to the fact that the producers sell their products only at irregular intervals. The survey population rather includes all Germany-based enterprises which regularly buy and/or market products of the above NACE groups or compile associated statistics. 1.7 Survey units The survey units are legally independent enterprises, public authorities or instiutions. 1.8 Legal bases EU law No EU law as a legal basis Federal law Price Statistics Law in the amended version published in the Federal Law Gazette, Part III, Subsection No , last amended by Article 20 of the law of 7 September 2007 (Federal Law Gazette I, p. 2246); Ordinance Implementing the Price Statistics Law of 29 May 1959 (Federal Bulletin No. 104, p. 1), last amended by Article 5 of the Ordinance of 20 November 1996 (Federal Law Gazette I, p. 1804), in conjunction with the Federal Statistics Law (BStatG) of 22 January 1987 (Federal Law Gazette I, p. 462, 565), last amended by Article 3 of the Law of 7 September 2007 (Federal Law Gazette I, p. 2246) Land law No Land law as a legal basis Other bases No other legal basis. 1.9 Confidentiality and data protection The individual data collected are generally kept secret according to Article 16 of the Federal Statistics Law. Only in a small number of exceptional cases explicitly regulated by law may individual data be passed on. The names and addresses of the respondents are never passed on to third parties. Pursuant to Article 16, para. 6 of the Federal Statistics Law, individual data may be passed on to institutions of higher education or other institutions entrusted with independent scientific research for the purpose of carrying out scientific projects, if such data have been anonymised in a way that identifying the relevant respondents or parties concerned would require an unreasonable effort in terms of time, cost and manpower. Persons receiving individual data are also obliged to adhere to the principle of confidentiality. 2 Purpose and goals of the statistics 2.1 Survey content In the context of regular price collection, the survey covers the purchase prices (excluding VAT) of selected agricultural products. However, the description of goods is often less detailed compared to many other price statistics because the actual characteristics of the agricultural products often vary due to different climatic and other conditions and therefore cannot be monitored in a standardised manner. To the extent possible, the specification of agricultural products comprises all price-determining characteristics (e.g. buyer s stage in the economic process, type of forwarding, delivery terms, discounts/surcharges, type of packaging, quantity purchased/delivered, terms of payment). 3

4 Where information is derived from market reports or other statistics, product categories that are comparable to the preselected agricultural products are selected for price observation over time. The price information collected is to relate to products purchased or marketed in the reference month. 2.2 Purpose of the statistics The purpose of the statistics is to compile an index of producer prices of agricultural products, which illustrates how the revenues of agricultural holdings develop for a given production. The statistics are used by the European Commission and, at the national level, by the Federal Ministry of Consumer Protection, Food and Agriculture for planning agricultural policies. Furthermore, the statistics are generally used as an indicator of short-term economic trends, especially with regard to the development of prices of agricultural products at the producer stage. Besides, the index is frequently used as a basis for indexing payments agreed by contract for a longer period (stable-value clauses). And it is used to deflate other values of economic statistics, such as agricultural turnover. 2.3 Major users of the statistics At the international level, the European Commission is the main user of the statistics of producer prices of agricultural products. At the national level, the statistics are mainly used by various federal ministries, especially the Federal Ministry of Consumer Protection, Food and Agriculture. Other users of the statistics are agricultural associations and special interest groups. In addition, the statistical results are often used by contracting parties for agreements based on stablevalue clauses. 2.4 User involvement The users mainly get involved when another base year is specified for the statistics (usually every 5 years). On this occasion, in particular requests concerning the publication programme and proposals for updating the specifications of survey items are taken into account. 3 Survey methodology 3.1 Type of data collection Various sources of data are used to compile the statistics of producer prices of agricultural products. As with most other price statistics, a regular survey is carried out for certain product groups. Rather generally worded descriptions are given for the agricultural products included as survey items. To the extent possible, the responding enterprises at first have to refine the descriptions to provide more detail on the products they buy regularly and presumably over a longer period of time. Future price reports by the enterprises must relate to the detailed specifications. The data are collected in writing. The prices to be reported do not relate to a specific reference day, they rather refer to the reference month as a whole. Response is mandatory in this survey. The obligation to provide information rests with the owners or managers of the enterprises. For other product groups, reports of central market institutions are evaluated or data of agencies are used which compile market statistics for their own field of work (Federal Agency for Agriculture and Food). Series of index numbers are obtained by monitoring the prices of selected product categories in the statistics over time. 3.2 Sampling procedure Sampling design A regular survey is conducted for those product groups whose prices are not available from other statistics, market reports, etc. The sample is drawn using the method of purposive selection, which is commonly applied in price statistics, and with the selection carried out by the Federal Statistical Office as the data collecting agency Sample size, sampling fraction and sampling unit Some 250 enterprises or local units are covered by a regular survey to collect data for certain product groups Sample stratification No explicit stratification is carried out according to the method of purposive selection (see 3.2.1). However, care is taken to ensure that the sample reflects the most important variables in the scope of the survey, i.e. the main trading activities, size and regional distribution of the enterprises Expansion An expansion is not made. The result is a weighted average of the price trends observed for the agricultural products surveyed. 3.3 Seasonal adjustment procedure None. 4

5 3.4 Data collection tools and reporting channel On the one hand, the Federal Statistical Office evaluates statistics and market reports of relevant agencies. The regular survey is undertaken centrally by the Federal Statistical Office using a printed questionnaire. 3.5 Burden on the respondents To reduce the burden imposed on potential reporting units, existing statistics and market reports are evaluated to the extent possible. A survey as such is only conducted to cover the product groups for which statistics or market reports are not available. In carrying out the survey, the size of an enterprise is taken into account. Compared to bigger enterprises, smaller enterprises have to provide price information on a significantly smaller number of survey items. 3.6 Documentation of the questionnaire The questionnaire is available on request (only in German). 4 Accuracy 4.1 Overall qualitative assessment of accuracy The index of producer prices of agricultural products is calculated as an index number with one decimal place. The results are preliminary for a given reference month because some price reports are submitted with a considerable delay. When the index is rebased to a more recent base year, the use of new calculation bases (selection of survey items, weighting patterns) causes minor revision differences in the rates of price change as compared to those published for the former base year. 4.2 Sampling errors The sampling error cannot be quantified because the sample is not based on random selection. However, the method of purposive selection that is used in constructing the sample ensures a high degree of representativity. The product groups for which information is available from other statistics or market reports are partly covered in full Standard error None Biases due to the data expansion procedure None, because an expansion procedure is not applied. 4.3 Non-sampling errors Errors due to coverage This group of errors comprises both incorrect or inaccurate data of enterprises and non-response. Typically, incorrect or inaccurate data are corrected in the context of plausibility checks or by directly contacting the given enterprises in the reference month. Another error component is that of unit prices (price per kilogramme, etc.) which are incorporated in the index calculation when other statistics and market reports are evaluated. In that case, structural shifts in the pricedetermining characteristics of the product categories lead to deviations of the calculated index number from the "real" index number Unit non-response In the case of temporary non-response: see item non-response In the case of final non-response, a comparable survey unit is selected to replace the non-responding unit Item non-response In the case of temporary non-response: extrapolation, see imputation methods In the case of final non-response, the prices of a similar product within the same product category are collected (see 3.1). In the case of non-response towards the close of the season: see imputation methods Imputation methods In isolated cases, the price trend is extrapolation using price data collected for the same agricultural product from other reporting units. If price data are neither available from other units, the relevant price trend is extrapolated in line with the development of the prices of an aggregate. If non-response occurs towards the close of the season, the price is extrapolated using the last price collected More detailed analyses of the systematic error More detailed analyses of the systematic error are not made. 5

6 4.4 Continuous revisions As the results are preliminary for a given reference month (see 4.1), they may be revised at the time the final results become available and may then be referred to as past results in the context of the regular publication. In addition, revisions are made at five-year intervals when the index is rebased to a new base year. On that occasion, the results are fully recalculated from the start of the new base year Extent of revision Revisions are made without consideration of any differences between the revised or non-revised results Reasons for revision The basket of agricultural products whose prices are collected and the weights attached to those products must be updated regularly to ensure that the results truly represent the agricultural products sold. In accordance with international practice, this is done every five years. 4.5 Extraordinary sources of error Extraordinary sources of error include unexpected circumstances which affect considerably the use of preliminary or final results and therefore have to be pointed out in a special form. Such phenomena comprise, for instance, particularly important reports which are inaccurate or delayed and (natural) phenomena which lead to a strong modification of the survey object directly after the survey so that the informative value of the statistics is deteriorated. Such circumstances were not observed in this case. 5 Timeliness and punctuality 5.1 Timeliness of preliminary results Regular results for the reference month, which include some preliminary items, are published about 6 weeks after the reference month. 5.2 Timeliness of final results Final results are published about 15 weeks after the reference month. 5.3 Punctuality All publication deadlines are met. 6 Comparability over time and space 6.1 Qualitative assessment of comparability The Laspeyres concept used for the index of producer prices of agricultural products is based on the principle of all calculation bases being constant (selection of survey items and price representatives, sample of reporting units), which in theory ensures the comparability over time of the calculated indices within a base period. In practice, however, that principle cannot always be implemented. In the case of permanent non-response, changes have to be made especially in the composition of the sample of reporting units, which impairs comparability in the narrow sense. Adjustments in the selection of price representatives that become necessary over time are assessed by means of suitable quality adjustment methods. This means that price changes resulting from quality changes are eliminated from the price development. The calculation bases mentioned are kept constant over a base period, which is generally 5 years. Price indices for different base periods are often chain-linked to form long-term index series, although strictly speaking they are not comparable. The price trend shown in this way includes non-genuine price changes, i.e. price changes resulting, for example, from different weighting structures in the base periods. Regional comparability of the index of producer prices of agricultural products, which is calculated for Germany as a whole, is ensured for data from For earlier periods, results are available only for the former territory of the Federal Republic of Germany. Producer price indices for agricultural products are not available for the Länder. 6.2 Changes affecting comparability over time As regards comparisons between different base periods, it should be noted that the weights of the agricultural products differ which were included in the indices. Apart from that, the range of agricultural products included in the indices (basket of goods) is different. 6

7 7 Connection with other surveys 7.1 Input for other statistics Agricultural total account as well as deflationing of values of economic statistics. 7.2 Differences regarding other comparable statistics or results The index of producer prices of agricultural products is part of the system of German price statistics, which shows price trends for all major stages in the economic process. Besides the index of producer prices, an index of purchase prices of the means of agricultural production is computed for the agricultural sector. As regards the production stage, producer price indices for forestry and industrial products and construction price indices are computed in addition to the index of producer prices of agricultural products. Producer price indices for services are currently being set up. At the distribution stage, the system of price statistics contains indices of wholesale prices and of retail prices. The stage of final consumption of households is covered by consumer price indices. Price trends in transactions with foreign markets are shown by import and export price indices. 8 Other information sources 8.1 Publication channels, order address The results of the producer prices of agricultural products are offered in an electronic form only. At > Publikationen Thematische Veröffentlichungen Preise, Fachserie 17, Reihe 1 can be obtained free of charge as a PDF file. Through the database system GENESIS-Online ( > Zahlen & Fakten > Datenbanken > Genesis-Online > 61 > 612 > > Tabellen), detailed results of the Index of producer prices of agricultural products can directly be loaded in various file formats (.xls,.html and.csv). 8.2 Contact information Federal Statistical Office Gustav-Stresemann-Ring Wiesbaden Germany tel: +49 (0) 611 / fax: +49 (0) 611 / (keyword: Agrarpreise) 8.3 Further publications Papers on the producer prices of agricultural products are contained in the cross-section publication Wirtschaft und Statistik ( > Publikationen > Wirtschaft und Statistik), e.g.: Vorholt, Hubert: "Zur Neuberechnung der Indizes für die Landwirtschaft", 3/2001, p. 203 Further information on the Index of producer prices of agricultural products can be found at > Facts & Figures > Prices. 7