U.S. Census BureauInternational Programs Center

www.census.gov/ipc/www

Microcomputer Processing of

Census and Surveys(using CSPro)

Data File Design

• How are data stored in the data file?

• What is a case?• What is on a record?• How many records?

Objectives:

1. Understand elements of a data file2. Describe a field, record, and questionnaire3. Describe data file structures4. Learn how the CSPro data dictionary

defines these elements

Needed information about data file

• Need identification fields• Need information / data fields• Need “SIZE” [how many characters] • Need valid values/codes

Data File StructureASCII/text

• ALL data on ONE record/line

• Different types of data on DIFFERENT record/lines

Data Processing/Data File Terminology

• Item/variable/field• Record• Questionnaire (Case)• Data file

Item/variable/field

• Is a single piece of information• Has the attributes of:

SizeTypeNumeric/Alphanumeric

Age

5 1SexM

Income- 9 8 7 . 6 5

Record• a collection of related items forming a single line

of information. For example: • Housing Record

contains information about the house

• Population Record Contains information about each person in the house

Case/Questionnaire

• all the records of all types for a processing unit such as a household

A data file is

• a collection of all the questionnaires (cases)

CSPro Data Dictionary

1. Field names/labels2. Field size3. Field location4. Field attributes5. Record names6. Record types7. Records ID’s8. Records allowed by type

Questionnaire sections

One Section ==> One record

From the questionnaire to the data file

(one record type)

From the questionnaire to the data file

(What are the data?)

From the questionnaire to the data file

(Where are the data?)

Data Dictionary describes the data file