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CENTS is a software package for tabulating, summarizing, and
displaying statistical tables in publishable form. CENTS was
developed originally to facilitate the tabulation of population and
housing data from national censuses throughout the world. However,
the system can be applied easily to other types of statistical data
such as those from agriculture censuses, labor force studies, or
educational surveys.
CENTS is the tabulation component of the Integrated Microcomputer
Processing System (IMPS), a series of software packages for entry,
editing, tabulation, estimation, analysis, and disseminationof census and
survey data. IMPS was developed by the of the U.S. Bureau of the Census.
Distribution of IMPS is funded jointly by the Bureau of the Census and the
U.S. Agency for International Development (USAID).
Tabulation Capabilities
- Complex Tabulations - A table need not represent a simple crossing
of data items. A single item may be tabulated in one or more tables
using different aggregations or breakdowns. Similarly, multiple items
may be tabulated in the same table in several ways.
- Multiple Tables - CENTS can produce multiple tables in a
single pass of the data file. The size of the tabulation program grows
as more tables or CENTS statements are added. Therefore, a
limiting factor for the number of tables is the size of the computer
memory.
- Universe Definition - The universe definition, that is, those
records being considered for tabulation, may vary from table to table
within a run and is completely under your control.
- Recoding - Data items can be recoded. This allows for grouping
of values and for creating new variables. A recoded item may be saved
for use in any table which requires recoding.
- Hierarchical Structure - A hierarchical structure for tables, such
as various levels of geography, can be produced with one pass of the
data through CENTS. The design of the language is such that
geographic coding schemes can be manipulated easily to allow the creation
of tables of totals and special aggregations. The total and up to five
other levels of hierarchy can be defined.
- Weighting - In support of survey data files, a weight or sampling
factor may be set for the entire data file or on a case by case basis.
CENTS can handle decimal weights as well as integer weights.
- Lookup File - CENTS can match information on the primary
input file with information on a secondary input file, or "lookup" file.
This lets you access historical data, other geographic codes, sample
weights, or other information which is required for the tabulations.
- Extract File - CENTS can create a file which contains any
combination of data from the input file, lookup file, or derived
variables. This allows you to create an alternate output data file or a
specialized report.
Table Presentation
CENTS has a powerful and flexible interactive facility
for designing tables, performing final tablecalculations, and printing
the tables. Depending on the printing device available, the tables
produced by CENTS can be publication quality.
- Designing Tables - CENTS has an interactive facility to
design tables. This feature allows subject-matter specialists to design
their tables using CENTS.
- Statistical Measures - CENTS can produce statistical
measures such as sums, differences, means, medians, and percent
distributions. In calculating medians, a linear approximation technique
is used. However, CENTS is not a statistical analysis package and
cannot perform complicated statistics such as correlation, analysis of
variance, or regression.
- Text Definition - CENTS provides maximum flexibility in the
display of text and table cells. You have the option of specifying table
formats in great detail.
- Previewing Tables - CENTS lets you test and verify table
formats before data are tabulated. You can preview the tables and
visually verify the headings, stubs and other text, as well as the table
calculations such as row and column sums, percentages, and averages. This
feature allows subject-matter specialists to review the formats and make
changes.
- Geographic Name File - The function of defining text for geographic
areas is separate from other text definition. You can create a
generalized area name file which can be used in other CENTS applications. A good example of this is creating a computerized national
geographic coding scheme.
- Table Reformatting - Because an internal representation of the
table is saved between the tabulation and presentation phases, the tables
can be printed with different headings or stubs without retabulating the
data. This is important, especially if the tables are from census data
and errors are only in the text.
- Table Cell File - CENTS can produce a file containing the
table cell values which appear in the printed table. This file can be
used as input data to CENTS or to spreadsheet, graphics, or
mapping packages to further manipulate and display the tabulated data.
It also can be used to distribute tabulated data to users in computer
readable form.
Input Data Requirements
CENTS is capable of processing very large data files efficiently. There are no
restrictions on the number of questionnaires or records processed.
The files to be tabulated by CENTS must meet the following
requirements:
- The data file must be sequential.
- All items must be in fixed positions on the records.
- All records for a particular questionnaire must be physically adjacent on the file.
- A unique questionnaire identification code must be present in the
same location on each record. All records belonging to the same
questionnaire must have the same code. This condition may be satisfied
by a collection of fields giving geographic coding information and a
household number which is unique within the lowest geographic level.
- If there is more than one record type, each record must have a
record type code in a fixed position and of a fixed length.
Processing Methodology
CENTS provides an easy-to-use programming language for
tabulation of data. It performs acomprehensive analysis of your program
to clearly identify and explain syntax errors before theprogram is used
to tabulate the data file. CENTS programs can be maintained
easily and, for the most part, can be understood by both programmers and
subject-matter specialists.
Through the CENTS language, you describe the tabulation process,
the summarization hierarchy (if any) and the format for printing the
tables. CENTS translates the tabulation instructions into a COBOL
program, which is then compiled and made into an executable format. It
can thenbe tested against sample data to be sure that it is logically
correct and that it produces the desired results. The process of testing,
correcting and retesting can be repeated until a logically correct
tabulation program is produced. This final version of the tabulation
program is used totabulate data from a census or survey.
Data Dictionary
To use CENTS, a description of the file to be processed must
be given. To create this description, you use the Data Dictionary
component of IMPS, which is provided with CENTS. The Data
Dictionary lets you give a name to each data item in the file, specify
its location within a data record and define the values it may have.
These values can be used by CENTS to test items forvalid values.
Performance
The speed of CENTS depends on the number of tabulations
being performed, the organizationof the file being tabulated, and the
type of microcomputer being used. On an 80386 microcomputer running at
20 MHz, CENTS runs at a speed of about 20,000 records per minute,
producing 13 typical census tabulations at two geographic levels.
Hardware and Software
- IBM PC or compatible
640K bytes of memory
- 10M bytes of disk storage
- Printer capable of 132 characters per line
- DOS 3.2 or higher
- Realia COBOL 2.0 or higher
The Realia COBOL compiler is NOT supplied with CENTS. It must
be purchased from asoftware supplier. The cost is approximately US $1000.
For more information about Realia COBOL contact:
Computer Associates Realia
2 Executive Drive
Ft. Lee, New Jersey 07024, USA
Telephone:1 (201) 592-0009
Fax: 1 (201) 585-6746
