The finding of preference reversals between SWTP and choice implies that willingness to pay does not provide a stable measure of the position of an object in a preference order}in our view, because there is no stable preference order to be measured. Like the
scope problem that was discussed in the preceding section, the context dependence of SWTP is an unavoidable consequence of basic cognitive and evaluative processes. it is not a result of defective procedures, and it will not be eliminated by
improved survey methods.