Categorical variable ; pre and post intervention

vmp

New Member
#1
Hi all, I really need help with this one.

I am trying to see if my population change their alcohol habits between before and after an psychosocial intervention.

We asked the participants : how many days per week do you consume alcohol ?
a. Never
b. 1 to 2 days per week
c. 3 to 4 days per week
d. 5 to 6 days per week
e. every days

We asked the same question a month later to the same participants after giving them an intervention.

I thought of using chi 2, but my groups are not independent. Which test do you think I should use ?

Thank you in advance.
 

Karabiner

TS Contributor
#4
So you have an ordinal variable which was measured twice in the same subjects.
The sign test could be used here.

With kind regards

Karabiner
 

hlsmith

Less is more. Stay pure. Stay poor.
#6
Agreed. To help in your searches, it can be called the Wilcoxon sign test and you typically apply it to the differences of the two measures to reveal a non-null difference.
 

Karabiner

TS Contributor
#7
Agreed. To help in your searches, it can be called the Wilcoxon sign test and you typically apply it to the differences of the two measures to reveal a non-null difference.
Just to add a bit more detail, if we find information about the Wilcoxon signed rank test
(which requiers interval level) , it must not be confused with the sign test (for ordinal
variables).

With kind regards

Karabiner