Interpretation of the Middle Anchor of Likert Scale
There has been substantial debate about using an even or odd number of
rating scale points in attitude scaling with surveys. When an
odd-numbered rating scale is used, researchers are confronted with an
issue: how to label the mid-point. Not surprisingly, research on
interpretation of the middle option finds a lack of consistency
regarding respondent interpretation of the midpoint (Baka, Figgou, &
Triga, 2012; Kalton, Roberts & Holt, 1980; Nadler, Weston, & Voyles,
2015). When respondents were allowed to choose the label they associated
with a rating scale mid-point, different labels were used for items
assessing attitudes towards capital punishment and Sunday observance,
suggesting different meanings for the middle response category as a
function of item content. Nadler et al. (2015) found interpretation of
the mid-point as “don’t care,” “no opinion,” “unsure,”
“neutral,” “equal/both,” and “neither” was found with a sample of
U.S. undergraduates asked about politics in the U.S. Baka et al. (2012)
found the mid-point was interpreted as lacking in knowledge or
indifferent, ambivalent, disputing aspects of the question, or had no
information on the topic. When respondents choose the mid-point as their
response, it is possible the respondents are telling us that they do not
have a response because they either have no opinion, are
unclear/uncertain what their opinions are, or don’t care; that they do
have a response and the response is that they have an opinion that is
moderate in intensity, or they do not understand the question, or have
no information about the topic. In sum, the question is: are the
mid-point Likert scale responses substantive or non-substantive?
In attitude scaling, if respondents have access to the necessary
information and neither agree nor disagree with the issues and they
choose the mid-point anchor to indicate their state of mind, the
response is a substantive response and it should be coded and add to the
composite scale score. On the other hand, a non-substantive response is
a response that does not contribute or add to the measurement of the
target attitude. However, the meaning of a non-substantive response is
unclear, as it is multifaceted and could indicate carelessness,
confusion, or intentional behavior (Francis & Busch, 1975). A
non-substantive response can be a DK response implying that respondents
cannot retrieve the relevant information from their long-term memory
because they either do not have that information or cannot retrieve the
information at the time to form an opinion. Alternatively, a
non-substantive response is a random response if respondents guess
because they do not understand the question or if they simply satisfice
because they do not wish to spend the effort to provide a thoughtful
response. It can also be a systematic but irrelevant response, due to
deliberate efforts to present a certain impression or to some
unconscious stable response style such as leniency, neutrality, or an
acquiescent response tendency.