Hi, my name is Nancy Aguirre. I am a research associate for an independent evaluation consultant and a Professional Expert at Mt. San Antonio College in California. One thing that’s been tricky for me is developing scales, and it seems like so many people have a preference for 5, 7, and even 10 point scales! My tip today is about using 7 point scales for Likert-type items.
Hot tip: When creating a Likert scale for survey instruments, it is best to use a 7-point Likert scale because it will give you more variance than a 5-point scale. But, at the same time, using anything higher than a 7-point scale might be too cognitively challenging, and people cannot mentally discriminate at such a precise level. In addition, it would reduce the reliability of your results. Bipolar scales (those with a neutral midpoint, which uses opposite ends such as “strongly agree” to “strongly disagree”) perform best with seven points. Whereas, unipolar scales (zero scale at the end, such as “not at all important”) perform best with five. Plus, offering a midpoint on a bipolar scale, indicating a neutral position, increases reliability. In addition, it is best to provide neutrality, as a mid-point, because this does not force respondents to choose one camp over another. Respondents would be forced to choose a side even if the stand they take is weak. It is important to allow respondents to voice impartiality if they are “on the fence” about a particular topic. Also, they might be inclined to acquiesce to positively worded statements, and a neutral option might reduce this effect.
Rad Resource: These two resources have been very helpful for me. The Measurement Imperative by Wittink and Bayer in Marketing Research (2003, Vol 15, Part 3, pages 19-22). I also use William Crano’s book, Principles and Methods of Social Research.