Universe
Definition
A universe defines the reference base for your calculations. In other words, it defines the individuals taken into account in the total.
- If the numeric values come from a closed question, then the universe will be calculated in the same way as it is in closed questions. Asking for the mean will not change the base (DK responses are always included).
- If the numeric data is continuous (open-ended), then the base for selected response (which is meaningless for a free numeric) is the same as the question base (in other words, the intervals or fixed values you might create do not change the base).
Example
Our sample size is 150 people, including 76 men and 74 women. We ask "What is your favourite colour?" to 100 people, and obtain the following result:
|
Favourite colour |
Men: 76 |
Women: 74 |
Sample: 150 |
|
Green |
20 |
10 |
30 people |
|
Red |
15 |
25 |
40 people |
|
Blue |
10 |
10 |
20 people |
|
Don't Know |
6 |
4 |
10 people |
|
Not asked |
25 |
25 |
50 people |
Imagine that we want to calculate the percentages, we will obtain the following table for the universe, with the following universe types:
- Use selected responses
- Use the question base
- Use answering base
- Use selected sub-population
- All interviews
Use selected responses
|
Base: 70 |
Counts |
Percentage |
|
Green |
30 |
42.9% |
|
Red |
40 |
57.1% |
|
Total |
70 |
100% |
This means that only the selected individuals will be taken into account in the total base, or 70 people. Note that in this instance, the response item "Blue" has been de-selected.
Use the question base
|
Base: 100 |
Counts |
Percentage |
|
Green |
30 |
30% |
|
Red |
40 |
40% |
|
Total |
100 |
100% |
Even if we have only selected the "Green" and "Red" answer categories: we ask for the calculations to be made on the base of people to whom we have asked the question, or 100 people. Note that in this instance, the response item "Blue" has been de-selected.
Use answering base
|
Base: 90 |
Counts |
Percentage |
|
Green |
30 |
33.3% |
|
Red |
40 |
44.4% |
|
Blue |
20 |
22.2% |
|
Total |
90 |
100% |
This means that the calculations will be made on the base of individuals who have given an answer to the question (excluding the system Non Answers) , or 100-10= 90 people.
Use selected sub-population
|
Base: 76 men |
Counts |
Percentage |
|
Green |
20 |
26.3% |
|
Red |
15 |
19.7% |
|
Blue |
10 |
13.2% |
|
Total |
76 |
100% |
This means that the calculations will be made on the base of the 76 men who have given an answer.
All interviews
|
Base: 150 |
Counts |
Percentage |
|
Green |
30 |
20% |
|
Red |
40 |
26.7% |
|
Blue |
20 |
13.3% |
|
Total |
150 |
100% |
This means that the calculations will be made on the base of the whole sample or 150 people.
- Question table base
- All interviews for question table