I am David Bernstein, owner of DJB Evaluation Consulting and Director of Evaluation for the General Commission on Religion and Race of the United Methodist Church.
There is a long running debate among Springsteen fans regarding whether Mary’s dress “waves” or “sways” in the song Thunder Road (1975, Born to Run). For many years, I insisted the dress waved, not swayed. At a Rock and Roll Hall of Fame exhibit featuring Springsteen memorabilia I saw his hand written lyrics. Sure enough “Mary’s dress swayed.”
In a similar manner, for years I was convinced that Likert-like scales needed a mid-point to represent “neither positive nor negative.” I was apparently not alone.
Some feel that a Likert scale is not a Likert scale unless there is a midpoint, multiple items/issues being probed, and parallel structure between the positive and negative perceptions on either side of the midpoint. See for example http://www.john-uebersax.com/stat/likert.htm.
The design of Likert Scales has previously been discussed on AEA365, for example Nyame-Mensah on February 14, 2016, Losby and Wetmore on December 27, 2012, and Aguirre on May 6, 2010 (http://aea365.org/blog/?s=Likert&submit=Go) as well as numerous times on EvalTalk.
Why Likert-like, not Likert? Likert scales should be empirically tested to demonstrate that the “distance” between each number on the scale is identical as interpreted by respondents and reliably used. Often there is neither time nor resources to do cognitive testing of surveys, although pre-testing is recommended. So Likert-like is one term that could be used. I call them rating scales to placate the perfectionists. Scales are ordinal, representing categories of perceptions, not interval, representing numerical differences, Scales are ordinal, and so the mean is only valuable as a relative sense-making symbol, not as a real numeric value.
As an evaluator who uses mixed-methods, I know the world is gray, not black and white. I know people can genuinely have a “neither positive nor negative” viewpoint. However, I have become convinced that many people receiving human and social services don’t really like to be negative towards the people providing their essential services, and use the midpoint to express themselves as being “less than positive.” The midpoint does nothing for those needing feedback about their services.
This is how I became a “forced choice” proponent. I will use a midpoint when appropriate, but more often than not, my scales are four point, not five point. I am now a forced-choice cheerleader, praising the virtues of even numbered scales. Unfortunately, midpoint scales wave, they don’t sway.
As Losby and Wetmore pointed out in their 2012 AEA365 post, some respondents may be using the mid-point to express that they have “no opinion” or that the question is “not applicable (N.A.) to them, so the choice of the midpoint actually creates an invalid result (measurement bias). Make sure to include a “not applicable” category if appropriate.
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