3 resultados para Multiarea optimal power flow
em Repositório digital da Fundação Getúlio Vargas - FGV
Resumo:
This paper investigates the importance of ow of funds as an implicit incentive in the asset management industry. We build a two-period bi- nomial moral hazard model to explain the trade-o¤s between ow, per- formance and fees where e¤ort depends on the combination of implicit ( ow of funds) and explicit (performance fee) incentives. Two cases are considered. With full commitment, the investor s relevant trade-o¤ is to give up expected return in the second period vis-à-vis to induce e¤ort in the rst period. The more concerned the investor is with today s pay- o¤, the more willing he will be to give up expected return in the second period by penalizing negative excess return in the rst period. Without full commitment, the investor learns some symmetric and imperfect infor- mation about the ability of the manager to obtain positive excess return. In this case, observed returns reveal ability as well as e¤ort choices. We show that powerful implicit incentives may explain the ow-performance relationship with a numerical solution. Besides, risk aversion explains the complementarity between performance fee and ow of funds.
Resumo:
This paper considers tests which maximize the weighted average power (WAP). The focus is on determining WAP tests subject to an uncountable number of equalities and/or inequalities. The unifying theory allows us to obtain tests with correct size, similar tests, and unbiased tests, among others. A WAP test may be randomized and its characterization is not always possible. We show how to approximate the power of the optimal test by sequences of nonrandomized tests. Two alternative approximations are considered. The rst approach considers a sequence of similar tests for an increasing number of boundary conditions. This discretization allows us to implement the WAP tests in practice. The second method nds a sequence of tests which approximate the WAP test uniformly. This approximation allows us to show that WAP similar tests are admissible. The theoretical framework is readily applicable to several econometric models, including the important class of the curved-exponential family. In this paper, we consider the instrumental variable model with heteroskedastic and autocorrelated errors (HAC-IV) and the nearly integrated regressor model. In both models, we nd WAP similar and (locally) unbiased tests which dominate other available tests.
Resumo:
This paper considers two-sided tests for the parameter of an endogenous variable in an instrumental variable (IV) model with heteroskedastic and autocorrelated errors. We develop the nite-sample theory of weighted-average power (WAP) tests with normal errors and a known long-run variance. We introduce two weights which are invariant to orthogonal transformations of the instruments; e.g., changing the order in which the instruments appear. While tests using the MM1 weight can be severely biased, optimal tests based on the MM2 weight are naturally two-sided when errors are homoskedastic. We propose two boundary conditions that yield two-sided tests whether errors are homoskedastic or not. The locally unbiased (LU) condition is related to the power around the null hypothesis and is a weaker requirement than unbiasedness. The strongly unbiased (SU) condition is more restrictive than LU, but the associated WAP tests are easier to implement. Several tests are SU in nite samples or asymptotically, including tests robust to weak IV (such as the Anderson-Rubin, score, conditional quasi-likelihood ratio, and I. Andrews' (2015) PI-CLC tests) and two-sided tests which are optimal when the sample size is large and instruments are strong. We refer to the WAP-SU tests based on our weights as MM1-SU and MM2-SU tests. Dropping the restrictive assumptions of normality and known variance, the theory is shown to remain valid at the cost of asymptotic approximations. The MM2-SU test is optimal under the strong IV asymptotics, and outperforms other existing tests under the weak IV asymptotics.