|Unit||Index 2015=100, NSA|
|Adjustments||Not Seasonally Adjusted|
For Latvia, indicator of the monthly change in the volume of industrial production assuming constant technology and unchanging input structure. The index is compiled according to Regulations of the European Council concerning short-term statistics and classifications as well as concepts and methods of the Methodology of Short-term Business Statistics, Interpretation and Guidelines (Eurostat). The index measures the real monthly change of production in mining and quarrying, manufacturing, electricity, gas, steam and air conditioning, and water supply sectors. The production index is based on the deflated turnover.
Classification: From 1996, NACE Rev. 1 is used to classify enterprises by kind of activities replacing ISIC Rev. 3 at the detailed level. Since 2003 till 2008, the NACE Rev. 1.1 was used. Since January 2009 the NACE Rev. 2 is introduced.
Scope of the data
Industrial coverage: All public and private enterprises belonging to the industries B – E of the NACE Rev. 2. The enterprises in the sample cover about 90 percent of total industrial production.
Producer price index is used as a deflator.
Source data collection programs
Source data timeliness
Timing of production observations: The data are collected monthly from reporting units on the 7th calendar day of each month for B-C sections units and 10th calendar day for D-E sections units.
Source data statistical techniques
Computation of lowest level indices: The primary data on sales are aggregated into classes and Paasche indices and are calculated for each of these classes. The result is divided by the sales in the previous month at constant prices and multiplied by 100 to give the lowest level indices.
Aggregation: The deflated 4-digit NACE level data are progressively aggregated to higher levels and divided by the constant price data at the corresponding level in the previous period to obtain the 3-, 2-digit NACE level indices and overall index (of these only the latter two are published). Separate indices are compiled at the aggregate level for mining, quarrying and manufacturing, electricity, gas and water supply, Main Industrial Groups (MIGs) and specific aggregate level for mining, quarrying and manufacturing, manufacturing excluding manufacture of refined petroleum products.
Linking of re-weighted index to historical index: A chain Paasche index is compiled to link the various periods.
Reference period: The three indices are compiled: 2015 = 100, previous period = 100, and corresponding period of the previous year = 100.
Procedures for non-response: Imputation is used to treat for non-response. For the estimation of the data on small enterprises (1–4 persons employed) administrative sources are used (the monthly VAT return of the State Tax Inspectorate). The same source is used for the estimation of data on the enterprises that have not responded, as well as earlier known values of production sold by the enterprise recalculated to working days of the reporting month. The weighting factors are adjusted for other non-respondents.
Other statistical procedures
Treatment of missing data: When data are temporarily missing because of seasonality or production stoppage, they are imputed by following the same procedures as in the case of non-response of sampled units (see above - procedures for non-response).
Adjustment for quality difference: From January 2006, the quality report for production index is presented each month.
Validation of intermediate results
Verification of data: Data are checked on enterprise level (micro level) and on macro level. If necessary, the data are verified by contacting the reporting unit. For verification, visual and logical controls are used.
Verification of processing: Staff regularly reviews the compilation process comparing the indices at various stages of compilation with other market information or using personal judgment. Exceptional variations in the indices are followed on a case-by-case basis.
Consistency with other indicators of industrial production: As part of the review process, the staff check that the movements of the indices are in line with the quantity data of individual products.