Test Construction using
Factor Analysis
Imagine that you have been asked to construct a personality test. You would
complete the following steps:
- Using your clinical knowledge, logic, and common sense, you would come up
with 100’s of questions that you believe relate to personality.
- You would then administer your test to as many subjects as possible.
- You would enter the responses into a computer in order to do a factor
analysis. This technique correlates every item on your test with every other
item on your test. The result is a set of "factors" or clusters of
items that seem to be intercorrelated.
- You would then look at the individual questions in each "factor"
and attempt to name them.
Here is an example of a test that only consists of 15 questions.
Subjects are asked to answer True of False to each question.
- I consider myself to be a very organized person.
- As a person, I possess many positive qualities
- I would rather spend time alone reading a good book or watching a movie
than going out with a group of people.
- Sometimes I feel that no one really likes me.
- I prefer coffee to tea.
- In any job, meeting deadlines is extremely important.
- I believe that most people would like me if they got to know me.
- My motto is "the more the merrier!"
- I enjoy attending parties.
- I often start new projects, but then lose interest and never finish them.
- People are always talking about me behind my back
- I would prefer to live in a small town rather than a big city.
- Many people waste too much of their lives worrying about "crossing
their T’s and dotting their I’s".
- I would enjoy being a librarian.
- I keep a very detailed day planner so I always know what I need to do each
day.
When you enter all responses from your entire sample, and conduct a factor
analysis, three factors appear.
FACTOR
I
FACTOR
II
FACTOR III
1
T
2
T
3 T
6
T
4
F
8 F
10
F
7
T
9 F
13
F
12 T
15 T
5. Now it your job to provide descriptors for these factors.