Crosstabulations
(Tables, Multiway Tables)
A crosstabulation table
is a combination of two (or more) frequency
tables arranged such that each cell in the resulting table represents
a unique combination of specific values of crosstabulated
variables. Thus, crosstabulation
allows us to examine frequencies of observations that belong to specific
combinations of categories on more than one variable. For example, the
following simple ("twoway") table shows how many adults vs.
children selected "cookie A" vs. "cookie B" in a taste
preference test:

COOKIE:
A 
COOKIE:
B 

AGE: ADULT 
50 
0 
50 
AGE: CHILD 
0 
50 
50 

50 
50 
100 
By examining these frequencies, we can identify relations
between crosstabulated variables
(e.g., children clearly prefer "cookie B"). Only categorical
(nominal) variables or variables
with a relatively small number of different meaningful values should be
crosstabulated. Note that in
the cases where we do want to include a continuous variable in a crosstabulation (e.g., income), we
can first recode
it into a particular number of distinct ranges (e.g., low, medium, high).
For more information, see the Crosstabulations
Introductory Overview.