1. Likert Scale

2. Likert Scale
2

3. Likert Scale
User
Response
Value
A
Agree
4
B
Neutral
3
C
Agree
4
D
Strongly agree
5
E
Disagree
2
The mean
would be:
4+3+4+5+2
5 responses
= 3.6
That means that the
users almost agree with
the UI of Wikipedia.
3

4. …and some statistics
• There are different kinds of variables:
 Categorical or nominal (e.g., colors)
 Ordinal (e.g., rate 1 to 10 your happiness)
 Interval. The difference between values can be
measured, and is the same (lineal intervals)
 Ratio. Same as before, but also 0 means 0. E.g.,
temperature measured in C, 0 does not mean the
absence of temperature.
4

5. …and some statistics
• What can we do ?
Nominal
Ordinal Interval
Ratio
Frequency
Yes
Yes
Yes
Yes
Median
No
Yes
Yes
Yes
Add, mean, std. deviation
No
No
Yes
Yes
Ratio, coef. of variation
No
No
No
Yes
5

6. References
• Jamieson, S (2004). "Likert Scales: How to
(Ab)use Them" Medical Education,
Vol. 38(12), pp.1217-1218
• de Winter, J. C. F.; Dodou, D. (2010). "Fivepoint Likert items: t test
versus Mann-Whitney-Wilcoxon", Practical
Assessment, Research & Evaluation,
Vol. 15(11).
6

7. Comments and Questions