Quantity-dependent part of the utility of Sales v i Error term specific to subject or product i v Value function of prospect theorȳ v Value function of reference point model w First derivative of the distortion function of Sales ξ Trust factor Z Random variable in trust model xvi This thesis is an extended version of Scheele et al. (2017), which is joint work with Ulrich Thonemann and Marco Slikker. It benefited from the comments of four anonymous referees and the editors of Management Science. Preliminary research results have been presented at the following conferences: