Saturday, October 27, 2012

The 4 point Likert Scale

I have always grown up with the idea of a 5 point Likert scale. But recently in my Market Research class, our prof. introduced us to the concept of 4 point Likert scale.
Likert scale is a very popular rating scale used to determine a respondents' agreement level.
The following image shows an examples of a 5 point Likert scale:



Likert scales are odd numbered scales. Most commonly used is the 5 point scale, some researchers also use the 7 point scale. Now, at times there are situations when a respondent chooses the 'Neutral' option in a 5 point Likert scale. Researchers have started using a 4 point scale in which there is no neutral option. This is done in order to extract a specific response from the respondents.
For the scale shown in the pic above, a 4 point Likert scale will have the following options:
Strongly agree, agree, disagree, Strongly disagree




4 point likert scale is also called a forced Likert scale since the user is forced to form an opinion. There is no safe 'neutral' option. A number of market researchers are using the 4 point scale to get specific responses. However there are pros and cons of the 4 point likert scale approach.

Subsequent research has shown that a 4 point likert scale influences the survey results a lot. Socially acceptable issues tend to be skewed towards the positive, whereas negative-influence issues tend to skew the responses towards the negative. A 4 point Likert scale is observed to distort the results. Statistically speaking, the data responses of a 4 point and 5 point Likert scale do not match. A 5 point Likert scale data is more accurate than the 4 point data. Moreover, most of the statistical softwares/tools can process only 5 point likert scale responses. Thus a 5 point likert scale data is considered to be more accurate and gives a better picture.
However, there might arise cases in which a specific user opinion is essential, a 4 point scale can be employed. It can be used for recording opinion on services/products which the user has used/experienced.



3 comments:

  1. We use a 4 point scale in our guest feedback forms. At times, its better not to fill the survey, than select the neutral option.

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  2. Yeah Ramnath, when a customer uses your service and the data collected wont be tested with statistical softwares, a 4 point scale makes more sense.

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  3. I agree with the principle that forcing a choice when a respondent has no opinion one way or the other or is on the fence reduces the validity of the responses. Respondents have to choose "agree" or "disagree" when they really DON'T.

    In many cases, it is preferable to know that they were neutral rather than having them not answer the question at all. That has the same effect as an artificially forced response. It increases the percentage of those who agree (for example), making it appear that a higher percentage agreed than actually did.

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