A Note on "Economically Optimal Performance Evaluation and Control Systems": The Optimality of Two-Tailed Investigations
在Baiman和Demski的多主体成本方差调查模型中，探讨当代理人使用非HARA类效用函数时，双尾调查（即同时调查过大和过小方差）成为最优的条件。
The cost variance investigation problem has been modeled in a multiperson setting by Baiman and Demski (BD) [1980a; 1980b ]. Their results include the Pareto optimality of one-tailed investigations of costs, wherein either very large or very small variances (but not both) should be investigated by the principal. One of the sufficient conditions for their result was that the agent have a utility function that belongs to the hyperbolic absolute risk aversion (HARA) class. While this class is rich (incorporating power, exponential, and logarithm utility functions), different functional forms may imply the optimality of two-tailed investigations. The purpose of this paper is to derive conditions under which two-tailed investigations are optimal within their model, assuming two non-HARA utility functions for the agent. In the next section I provide a brief description of the BD [1980b] model, the HARA assumption, the optimal investigation rule, and the optimal investigation region. This provides a basis for comparing results derived when a specific non-HARA utility function is assumed. In section 3 I substitute two non-HARA agent utility functions for the HARA form.