Surveying Farmers: A Case Study

A large percentage of farmers do not respond to mail surveys. To gain insight into why farmers do not respond and how to improve response rates, a three-step research design was developed. First, an initial survey, based on in-person interviews with 15 farmers, was sent to 100 farmers. Second, farmers who did not respond to this mail survey were contacted by phone to investigate the reasons for not responding. Third, based on the information from these nonrespondents, the survey instrument was revised and sent to 3,990 U.S. farmers. Our studies show that the period in which the survey is sent is a crucial factor in the willingness to participate, along with the form and amount of compensation, the sender of the questionnaire, and the perceived length of the questionnaire.     

An Examination of Option-Implied S&P 500 Futures Price Distributions

Expected S&P 500 futures price distributions are derived using no-arbitrage option pricing models. These distributions are parameterized both as the lognormal and as a less restrictive three-parameter Burr-XII distribution. The resulting option-based probability assessments display some evidence of miscalibration very near to expiration and far from expiration, but are accurate over intermediate time ranges. The means of the implied price distributions correspond closely to the contemporaneous futures prices for both distributions, although marginally better with the Burr-XII. The Burr-XII distribution also performs better than the lognormal based on calibration statistics, and hence, is used to recalibrate estimated distributions.     

一部集全球化问题之大成的佳作——保卫全球化

尽管关于饮食和减肥的书在数量上要远远超过关于全球化的书，但后者也并不短缺，那我们为什么要费心给大家介绍又一本全球化题材的书呢?     

Prospective utility study of patients with multiple cardiovascular events

Objectives: The effects of acute coronary syndrome (ACS) events on health-related quality-of-life (HRQoL) and the time dependency of these effects are unknown. This study aimed to characterize health utilities in ACS patients to aid development of future economic models estimating the cost per quality-adjusted life-year impact of ACS events and potential treatments.

Methods: Multi-center, non-interventional, longitudinal evaluation of health utility in patients experiencing ACS or stroke events. EuroQol-5 dimension 3 level (EQ-5D-3L) surveys were sent to patients (≥18 years) from three UK centers, 1 month after hospital discharge for myocardial infarction (MI), unstable angina (UA), or stroke. Patient demographics, lifestyle, and baseline utility score were collected in the first survey. Follow-up surveys were sent at 6, 12, 18, and 24 months to prospectively capture utility and subsequent health events. Two methods of patient identification were adopted—prospective, where the patient’s qualifying events occurred after the study index date, and retrospective, where the patient’s qualifying event occurred prior to the study index date. General healthy population utility values were assumed for pre-event HRQoL.

Results: Between January 2011 and March 2014, 2,103 prospectively (n?=?1,350)/retrospectively (n?=?753) identified patients (mean age?=?68.3 years; 67.9% male) responded: MI?=?55.9% (n?=?1,176), UA?=?42.7% (n?=?898), stroke?=?1.4% (n?=?29); 24% had type 2 diabetes. Post-event utility values were lower than general healthy population values, although significant differences in utility between subsequent 6 (n?=?1,031, change?=?–0.002), 12 (n?=?1,096, change?=?–0.008), 18 (n?=?1,246, change?=?–0.007), and 24 (n?=?1,277, change?=?–0.004) month timepoints were not detected. Through multivariate regression analyses, wheelchair use, current smoking, and secondary mental and joint health events were associated with the greatest statistically significant utility decrements.

Conclusions: This study indicates that health utility decreases following a cardiovascular event and, although some improvement occurs over the subsequent 24 months, general healthy population utility is not necessarily attained.     

A reality check on technical trading rule profits in the U.S. futures markets

This article investigates the profitability of technical trading rules in U.S. futures markets during the years 1985–2004. Statistical significance of performance across the trading rules is evaluated using White's Bootstrap Reality Check and Hansen's Superior Predictive Ability tests, which can directly measure the effect of data snooping by testing the performance of the best rule in the context of the full universe of technical trading rules. Results show that the best rules generate statistically significant economic profits for only two of 17 futures markets after correcting for data snooping biases. This evidence suggests that technical trading rules generally have not been profitable in the U.S. futures markets. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 30:633–659, 2010     

Identifying spatial interactions in the presence of spatial error autocorrelation: An application to land use spillovers

Spatial spillovers—interaction effects among neighboring agents in space—are a common characteristic of a variety of processes that are of interest to environmental and resource economists. Empirical identification of these interactions is challenging, however, due to the endogenous nature of the interactions and the inevitable unobserved spatial correlation that, if uncontrolled, can result in spurious estimates of the interaction parameters. Traditional spatial econometric models rely on maintained assumptions that impose separate structures for the spatial error and interaction processes and thus are insufficient for solving this identification problem. To identify spatial land use spillovers in a hedonic model of residential housing values, we pursue an alternative approach by exploiting a natural experiment in the data. We use exogenous physical land features that impose a direct constraint on residential development on some, but not all, of the land that falls within our study region and use this to construct a “partial population identifier.” We find that this estimation strategy solves the endogeneity problem and reduces spatial error autocorrelation, but does not fully eliminate it. Estimation of the model using a more restricted sample in combination with the partial population identification strategy is successful in eliminating the remaining spatial error autocorrelation. We conclude that less restrictive approaches to controlling for unobserved spatial correlation, such as the natural experiment pursued here, may provide a superior alternative to identifying spatial spillovers.