Couper, Mick P., Roger Tourangeau, Frederick G. Conrad, and Eleanor Singer. 2006. "Evaluating the effectiveness of visual analog scales - A web experiment." Social Science Computer Review, 24(2), 227-245.
The use of visual analog scales (VAS) in survey research has been relatively rare, in part because of operational difficulties. However web surveys permit the use of continuous input devices such as slider bars, making VAS more feasible. The authors conducted an experiment to explore the utility of a VAS in a web survey, comparing it to radio button input and numeric entry in a text box on a series of bipolar questions eliciting views on genetic versus environmental causes of various behaviors. The experiment included a variety of additional comparisons including the presence or absence of numeric feedback in theVAS, the use of a midpoint or no midpoint for the other two versions, and numbered versus unnumbered radio button scales. The response distributions for theVAS did not differ from those using the other scale types, and theVAS had higher rates of missing data and longer completion times.