Starting point anchoring effects in choice experiments

Anchoring is acknowledged as a potential source of considerable bias in Dichotomous Choice Contingent Valuation studies. Recently, another stated preference method known as Choice Experiments has gained in popularity as well as the number of applied studies. However, as the elicitation of preferences in Choice Experiments resembles the Dichotomous Choice format, there is reason to suspect that Choice Experiments are equally vulnerable to anchoring bias. Employing different sets of price levels in a so-called Instruction Choice Set presented prior to the actual choice sets, the present study finds that preferences elicited by Choice Experiments can be subject to starting point anchoring bias. Different price levels provoked significantly different distributions of choice in two otherwise identical choice set designs. On a more specific level, the results indicate that the anchoring subjectivity in the present study is gender dependent, pointing towards, that female respondents are prone to be affected by the price levels employed. Male respondents, on the other hand, are not sensitive towards these prices levels. Overall, this implicates that female respondents, when employing a low-priced Instruction Choice Set, tend to express lower willingness-to-pay than when higher prices are employed.