Chained CPI-All Urban Consumers (SU) su.txt Section Listing 1. Survey Definition 2. FTP files listed in the survey directory 3. Time series, series file, data file, & mapping file definitions and relationships 4. Series file format and field definitions 5. Data file format and field definitions 6. Mapping file formats and field definitions 7. Data Element Dictionary =================================================================================== Section 1 =================================================================================== The following is a definition of: CHAINED CONSUMER PRICE INDEX - All Urban Consumers (SU) Survey Description: The Chained Consumer Price Index for All Urban Consumers, was introduced with the release of July data in August 2002. Designated the C-CPI-U, the index supplements the existing Consumer Price Indexes already produced by the BLS: the CPI for All Urban Consumers (CPI-U) and the CPI for Urban Wage Earners and Clerical Workers (CPI-W). The C-CPI-U employs a Tornqvist formula and utilizes expenditure data in adjacent time periods in order to reflect the effect of any substitution that consumers make across item categories in response to changes in relative prices. The new measure is designed to be a closer approximation to a "cost-of-living" index than the present measures. The use of expenditure data for both a base period and the current period in order to average price change across item categories distinguishes the C-CPI-U from the existing CPI measures, which use only a single expenditure base period to compute the price change over time. In 1999, the BLS introduced a geometric mean estimator for averaging prices within most of the index’s item categories in order to approximate the effect of consumers’ responses to changes in relative prices within these item categories. The geometric mean estimator is used in the C-CPI-U in the same item categories in which it is used in the CPI-U and CPI-W. Expenditure data required for the calculation of the C-CPI-U are available only with a time lag. Thus, the C-CPI-U is issued first in preliminary form using the latest available expenditure data at that time and will be subject to multiple revisions, with the final index published 10-12 months after the initial estimate. The C-CPI-U index revisions are expected to be small, but in principle each monthly index could be revised from its previously published level. The C-CPI-U will be issued for national averages only and will not be seasonally adjusted. It employs a December 1999=100 reference base. Data for periods prior to December 1999 will not be calculated. The component series that will be published are listed below: ==================================================================================== Section 2 ==================================================================================== The following Chained CPI-All Urban Consumers Data files are on the BLS internet in the sub-directory pub/time.series/su: su.area - Area codes mapping file su.base - Base codes mapping file su.data.0.Current - All current year-to-date data su.data.1.AllItems - All item data su.footnote - Footnote codes mapping file su.item - Item codes mapping file su.series - All series and their beginning and end dates su.txt - General information ================================================================================= Section 3 ================================================================================= The definition of a time series, its relationship to and the interrelationship among series, data and mapping files is detailed below: A time series refers to a set of data observed over an extended period of time over consistent time intervals (i.e. monthly, quarterly, semi-annually, annually). BLS time series data are typically produced at monthly intervals and represent data ranging from a specific consumer item in a specific geographical area whose price is gathered monthly to a category of worker in a specific industry whose employment rate is being recorded monthly, etc. The download.bls.gov files are organized such that data users are provided with the following set of files to use in their efforts to interpret data files: a) a series file (only one series file per survey) b) mapping files c) data files The series file contains a set of codes which, together, compose a series identification code that serves to uniquely identify a single time series. Additionally, the series file also contains the following series-level information: a) the period and year corresponding to the first data observation b) the period and year corresponding to the most recent data observation The mapping files are definition files that contain explanatory text descriptions that correspond to each of the various codes contained within each series identification code. The data file contains one line of data for each observation period pertaining to a specific time series. Each line contains a reference to the following: a) a series identification code b) year in which data is observed c) period for which data is observed (M13, Q05, and S03 indicate annual averages) d) value e) footnote code (if available) ================================================================================= Section 4 ================================================================================= File Structure and Format: The following represents the file format used to define su.series. Note the Field Numbers are for reference only; they do not exist in the database. Data files are in ASCII text format. Data elements are separated by spaces; the first record of each file contains the column headers for the data elements stored in each field. Each record ends with a new line character. Field #/Data Element Length Value(Example) 1. series_id 17 SUUR0000SA0E 2. area_code 4 0000 3. item_code 8 SA0E 4. seasonal_code 1 U 5. periodicity_code 1 R 6. base_code 1 S 7. base_period 20 DECEMBER 1999=100 8. footnote_codes 10 It varies 9. begin_year 4 1999 10. begin_period 3 M12 11. end_year 4 2003 12. end_period 3 M01 The series_id (SUUR0000SA0E) can be broken out into: Code Value(Example) survey abbreviation = SU seasonal_code = U periodicity_code = R area_code = 0000 item_code = SA0E ================================================================================== Section 5 ================================================================================== File Structure and Format: The following represents the file format used to define each data file. Note that the field numbers are for reference only; they do not exist in the database. Data files are in ASCII text format. Data elements are separated by spaces; the first record of each file contains the column headers for the data elements stored in each field. Each record ends with a new line character. The su.data file is partitioned into four separate files: 1. su.data.0.Current = All current year-to-date data 2. su.data.1.Items = All items Both of the above data files have the following format: Field #/Data Element Length Value(Example) 1. series_id 17 SUUR0000SA0 2. year 4 1999 3. period 3 M12 4. value 12 100.0 5. footnote_codes 10 It varies The series_id (SUUR0000SA0E) can be broken out into: Code Value(Example) survey abbreviation = SU seasonal_code = U periodicity_code = R area_code = 0000 item_code = SA0E ============================================================================ Section 6 ============================================================================ File Structure and Format: The following represents the file format used to define each mapping file. Note that the field numbers are for reference only; they do not exist in the database. Mapping files are in ASCII text format. Data elements are separated by tabs; the first record of each file contains the column headers for the data elements stored in each field. Each record ends with a new line character. File Name: su.area Field #/Data Element Length Value(Example) 1. area_code 4 A100 2. area_name 80 Text File Name: su.base Field #/Data Element Length Value(Example) 1. base_code 1 S 2. base_name 20 Text File Name: su.footnote Field #/Data Element Length Value(Example) 1. footnote_code 1 I 2. footnote_text 100 Text File Name: su.item Field #/Data Element Length Value(Example) 1. item_code 8 SA0L1E 2. item_name 100 Text ============================================================================== Section 7 ============================================================================== CHAINED CPI-ALL URBAN CONSUMERS(SU) DATABASE ELEMENTS Data Element Length Value(Example) Description area_code 4 A100 Unique code used to identify a specific geographic area. area_name 80 Text Name of specific geographic Ex: MIAMI, FLA area. begin_period 3 M02 Identifies first data observation Ex: M02=Feb within the first year for which (M=Monthly, M13= data is available for a given time Annual Avg) series. begin_year 4 1990 Identifies first year for which data is available for a given time series. end_period 3 M06 Identifies last data observation Ex: M06=June within the last year for which (M=Monthly, M13= data is available for a given time Annual Avg) series. end_year 4 2000 Identifies las year for which data is available for a given time series. footnote_code 1 It varies Identifies footnotes for the data series. footnote_codes 10 It varies Identifies footnotes for the data series. footnote_text 100 Text Contains the text of the footnote. item_code 8 SA0L1E Identifies item for which data observations pertain. item_name 100 Text Full names of items. series_id 17 SUUR0000SA0E Code identifying the specific series. value 12 100.2 Average data value for series. year 4 1990 Identifies year of observation.