Testing Distributional Dependence in the Becker-DeGroot-Marschak ...

instructions reported elicitations of $0 more often than those with basic instructions regardless of
the distribution faced in round 2.
4.2 Results on Mass
The data provide compelling evidence that the position of mass in the distribution of random
prices can have a pronounced effect on the WTP elicitations across subjects. More mass to the
right often leads to higher WTP elicitations. This is suggested at first glance by the descriptive
statistics given in Table 4. The pairwise comparisons that appear in Table 6, Table 7, and Table
8, often show significant difference in average WTP across distributions. This is true even though
these tables are based only on the last elicitations, which should exhibit less distributional
sensitivity than either the first elicitations or the entire set of observations. Furthermore, the
patterns and conditions under which the null statement of Hypothesis 2 is rejected are
enlightening.
Table 6 holds the support and the type (i.e., shape) of the distribution constant and focuses
on symmetric shifts in the location of mass within the fixed support. For five of the six resulting
pairs, the null of Hypothesis 2 is soundly rejected. Interestingly, the effect disappears in all cases
for the subjects who viewed detailed instructions.
Table 7 holds the shape of the distribution and the location of the mass fixed and varies the
support across the pairs considered. For all of the seven pairs of distributions the null of
Hypothesis 2 is rejected outright. That the effect is particularly strong when the support is
varied is unsurprising, since the elicitations for the distributions with higher support would
mechanically be higher if enough of the subjects remained unsure about whether it would be
possible or proper to submit values outside of a given distribution’s support. This table, then,
provides the clearest evidence that the detailed instructions had a substantial effect: for that set
of subjects only two of the seven pairs had significantly higher elicitations for the distribution
with higher support, and the level of significance was less pronounced.
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