Re: A 4 point Likert scale

Posted by Bruce Weaver on Oct 17, 2011; 8:28pm
URL: http://spssx-discussion.165.s1.nabble.com/A-4-point-Likert-scale-tp4910676p4911452.html

Interesting guidelines, Scott.  Thanks for posting.  However, re items 3 and 4 (see below), my sister (to whom I sent the link) wonders how would one distinguish between a deliberate choice to not respond and failure to notice the item?

Cheers,
Bruce

--- from the rules of thumb ---
3. Avoid "Not Applicable" or "No Opinion" response categories. It is far better to instruct respondents to skip irrelevant items than it is to offer them the opportunity in every item to seem to provide data, but without having to make a decision.

4. Avoid odd numbers of response options. Middle categories can attract disproportionate numbers of responses. Like "Not Applicable" options, middle categories allow respondents to appear to be providing data, but without making a decision. If someone really cannot decide which side of an issue they come down on, it is better to let them decide on their own to skip the question. If the data then show that two adjacent categories turn out to be incapable of sustaining a quantitative distinction, that evidence will be in hand and can inform future designs.

SR Millis-3 wrote

Without knowing more about the construct you're trying to measure, it's difficult to provide more than some very rough guidelines:

--Avoid odd numbers of response categories.

--Avoid "not applicable" or "no opinion" response categories.

--Consider starting with 6 categories.

For more guidance:
http://www.rasch.org/rmt/rmt203f.htm


~~~~~~~~~~~
Scott R Millis, PhD, ABPP, CStat, PStat®
Professor
Wayne State University School of Medicine
Email:  [hidden email]
Email:  [hidden email]
Tel: [phone]


________________________________
From: Mohamed Fawzy Afify <[hidden email]>
To: [hidden email]
Sent: Monday, October 17, 2011 2:26 PM
Subject: Re: A 4 point Likert scale


Thank you for your help.

The point is, I do not want to have a neutral position. This is not a construct.

so do you suggest a 6 point scale , giving more stretch and eliminating the neutral status?

However, I do have a construct [5 items] that was originally measured on a 4 point scale and I intend to use it.


Regards


Mohamed



________________________________
From: Art Kendall <[hidden email]>
To: Mohamed <[hidden email]>
Cc: [hidden email]
Sent: Monday, October 17, 2011 8:19 PM
Subject: Re: [SPSSX-L] A 4 point Likert scale


Why do you want to use only a 4 point Likert scale?
_The more you restrict the variance of a variable the more you
    restrict its possible covariance._
As a rule of thumb you want items to approximate a continuous
    construct as much as possible given who your respondents are.

An actual Likert item has 5 points SD D ? A SA.  Do you have a
    Disagree to Agree construct for your response scale?

If your scale has many items, the total (mean) score might not be
    too restricted.
If you do not have scales, but are measuring a construct with a
    single variable the restriction of variance and therefore on
    covariance is even more problematical.

In short, a 4 point response scale is usually inadvisable. Why
    coarsen your measurement any more than is really necessary?


Art Kendall
Social Research Consultants

On 10/17/2011 1:13 PM, Mohamed wrote:
Hi I intend to use a 4 point Likert scale format in my survey. I want to know if this puts limitations on the type of statistical analysis
tests conducted? Regards Mohamed --
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