Friday, March 19, 2010

Surveying: Stuck in the Middle

Here's some questions I have:

1. Given our state budget issues, do you think that the state sales tax should be increased or decreased?
2. Should more or less time be provided for Physical Education to students in North Carolina's public schools?
3. Do you feel more or less confident about our economy since November of last year?

What is true about each of my questions is that I could offer a middle response option if I used them in a survey (in other words a 5-point scale versus a 4-point scale). But should I?

From a cognitive standpoint, when surveyors do not offer a middle alternative, it is because they assume middle responses:
• consist largely of those who lean towards one or the other polar alternatives and thus feel it is legitimate to force a selection.
• tend to attract persons who have no opinion on the issue who would rather choose a non-committal middle response instead of saying "don't know" or "no opinion".

Surveyors who do offer middle alternatives assume that persons really do favor the middle position and if forced to choose one of the alternatives will contribute to random or systematic error.

So what does research tell us about offering a middle alternative?

Usually, if a middle alternative is offered,
1. 10-20% of respondents will choose that option
2. The decline appears to effect the polar alternative categories equally
3. Persons who have low "intensity" about a subject are most likely to choose a middle alternative . This may include those who have an absence of an opinion or ambivalence about their opinions. If persons have lower intensity about a subject and are not provided a middle alternative then there is a greater affect on responses than if persons have high intensity about a subject (and thus are less likely to use the middle alternative). The take home of this finding is: know your respondents.
4. Lack of or lower education does not appear to affect whether someone choose a middle response or not.
5. Cognition does affect choices which is why one should be careful how many choices children are provided on surveys.

For more information about this topic and other interesting survey research, see: Schuman and Presser's book: Questions and Answers in Attitude Surveys

No comments: