Five-point or seven-point Likert scale? I am designing a questionnaire by using five-point Likert scale. What is the advantage of five-point Likert scale over seven-point Likert scale? 
Thank you.
 A: In general what and how you intend to use the questionnaire makes a difference in practice. I have often only used 5 points because my subjects were often quite busy in daily life and return rates were higher with 5 points. With 7 points you get more data and I would think that might help in situations with low sample size.
I cannot find the actual paper, but this practical source might be helpful.
I might need to add, that I have not been doing many surveys in the last couple of years. The state of the art might have advanced and I am unaware of that...
A: I agree that from the responder viewpoint, seven point scales look more time consuming to answer. A bigger question would be, why an odd number? An even number forces a side of opinion. Imagine questions with social context. If everyone responded 3/5, would you rather interpret it to mean that no one cares about the question or that people are ambivalent about the issue? Perhaps then the sample needs better screening? Then imagine the same sample on a four point scale where 75% of response was 2/4. 
