Creating Crosstabulations (1)

Computing Frequency Distributions

Creating Crosstabulations

Two-Way Tables

So far, you have used the FREQ procedure to create one-way tables of frequency. The table results show total frequency counts for the values within the data set. However, it is often helpful to crosstabulate frequencies with the values of other variables. Census data, for example, is typically crosstabulated with a variable representing geographical regions.

The simplest crosstabulation is a two-way table. To create a two-way table, join two variables with asterisks (*) in the TABLES statement of a PROC FREQ step.

General form, TABLES statement for crosstabulation:

TABLES variable-1*variable-2 <* ... variable-n>;

where (for two-way tables)

variable-1 specifies table rows
variable-2 specifies table columns.

When crosstabulations are specified, PROC FREQ produces tables with cells that contain:

cell frequency
cell percentage of total frequency
cell percentage of row frequency
cell percentage of column frequency

For example, the following program creates the two-way table shown below.
proc format; value wtfmt low-139='< 140' 140-180='140-180' 181-high='> 180'; value htfmt low-64='< 5''5"' 65-70='5''5-10"' 71-high='> 5''10"'; run; proc freq data=clinic.diabetes; tables weight*height; format weight wtfmt. height htfmt.; run;

Frequency
Percent
Row Pct
Col Pct

Table of Weight by Height

Weight Height Total

< 5'5" 5'5-10" > 5'10"

< 140 2
10.00
100.00
28.57 0
0.00
0.00
0.00 0
0.00
0.00
0.00 2
10.00

140-180 5
25.00
50.00
71.43 5
25.00
50.00
62.50 0
0.00
0.00
0.00 10
50.00

> 180 0
0.00
0.00
0.00 3
15.00
37.50
37.50 5
25.00
62.50
100.00 8
40.00

Total 7
35.00 8
40.00 5
25.00 20
100.00

Note that the first variable, Weight, forms the table rows and the second, Height, forms the columns; reversing the order of the TABLES statement would reverse their positions in the table.