User Guide

199

File Handling a

nd Fi le Transformations

Deciding How to Restructure the Data

A variable contains information that you want to analyze—for example, a

measurement or a score. A case is an observation—for example, an individual. In a

simple data

structure, each variable is a single column in your data and each case

is a single row. So, for example, if you were measuring test scores for all students

in a class, all score values would appear in only one column, and there would be a

row for eac

h student.

When you analyze data, you are often analyzing how a variable varies according

to some condition. The condition can be a specific experimental treatment, a

demograph

ic, a point in time, or something else. In data analysis, conditions of

interest are often referred to as factors. When you analyze factors, you have a

complex data structure. You may have information about a variable in more than one

column in

your data (for example, a column for each level of a factor), or you may

have information about a case in more than one row (for example, a row for each

level of a factor). The Restructure Data Wizard helps you to restructure files with a

complex

data structure.

The structure of the current file and the structure that you want in the new file

determine the choices that you make in the wizard.

How are the data arranged in the c urrent file? The current data may be arranged so that

factors

are recorded in a separate variable (in groups of cases) or with the variable

(in groups of variables).

 Groups of cases. Does the current file have variables and conditions recorded

in sepa

rate columns? For example:

var

factor