Same-sex sexual behaviour: US frequency estimates from survey data with simultaneous misreporting and non-response

Survey-based research concerning sexual behaviour almost inevitably confronts the simultaneous problems of misreporting and non-response. These problems lead to disparities among estimates of the number and characteristics of those who engage in same-sex sexual behaviour. This paper proposes a statistical model to consistently estimate the frequency of same-sex sexual behaviour in the presence of non-ignorable misreporting and non-response. The model is fitted using 1991–2000 General Social Survey data. Frequency estimates corrected for simultaneous misreporting and non-response are reported. According to the model, 7.1% of US males and 4.1% of females – 15.8 million individuals – are not exclusively heterosexual. Allowing for misreporting and non-response increases the estimated same-sex frequency by more than four million. The model reveals new patterns between misreporting and non-response probabilities and standard demographic variables such as age and income.     

Fractional cointegration and futures hedging

This article examines the performance of various hedge ratios estimated from different econometric models: The FIEC model is introduced as a new model for estimating the hedge ratio. Utilized in this study are NSA futures data, along with the ARFIMA-GARCH approach, the EC model, and the VAR model. Our analysis identifies the prevalence of a fractional cointegration relationship. The effects of incorporating such a relationship into futures hedging are investigated, as is the relative performance of various models with respect to different hedge horizons. Findings include: (i) Incorporation of conditional heteroskedasticity improves hedging performance; (ii) the hedge ratio of the EC model is consistently larger than that of the FIEC model, with the EC providing better post-sample hedging performance in the return–risk context; (iii) the EC hedging strategy (for longer hedge horizons of ten days or more) incorporating conditional heteroskedasticty is the dominant strategy; (iv) incorporating the fractional cointegration relationship does not improve the hedging performance over the EC model; (v) the conventional regression method provides the worst hedging outcomes for hedge horizons of five days or more. Whether these results (based on the NSA index) can be generalized to other cases is proposed as a topic for further research. © 1999 John Wiley & Sons, Inc. Jrl Fut Mark 19: 457–474, 1999     

Coupling urban expansion models and hydrological models: How important are spatial patterns?

It is well known that urban expansion has a severe impact on the surface water balance by transforming vegetated covers into sealed surfaces. This transformation causes changing fluxes of evapotranspiration, surface runoff and groundwater recharge. In order to estimate the impact of land cover changes on the surface hydrology, hydrological models are often coupled with different types of land cover change models. It is, however, not clear to what extent spatially-explicit urban expansion scenarios provide an added value in comparison with non-spatial urban expansion models at different scale levels. The objective of this paper is to acquire a better insight in the importance of scale effects involved in the coupling of urban expansion scenarios and hydrological models. The relative importance of using different projections of both (i) quantity and (ii) spatial patterns of urban expansion was analysed at four different scale levels. The highly urbanised Flanders–Brussels region was taken as an example application. Twelve different urban expansion scenarios for 2025 and 2050 were developed and subsequently used as an input in a spatially-distributed water balance model. The results obtained suggest that at the level of the Flanders–Brussels region, an accurate estimation of the quantity of urban expansion should get priority over an accurate projection of the spatial patterns. However, the importance of using accurate projections of the spatial pattern of urban expansion increases systematically at local scale levels. A uniform strategy for coupling urban expansion models and hydrological models thus seems inappropriate. These findings are highly relevant for water management and spatial planning policymakers that typically operate at different administrative levels.     

Volatility and Price Jumps in Agricultural Futures Prices—Evidence from Wheat Options

Evidence suggests that agricultural futures price movements have fat-tailed distributions and exhibit sudden and unexpected price jumps. There is also evidence that the volatility of futures prices is time-dependent both as a function of calendar-time (seasonal effect) and time to maturity (maturity effect). This article extends Bates' (1991) jump-diffusion option pricing model by including both seasonal and maturity effects in the volatility specification. Both in-sample and out-of-sample procedures to fit market option prices on wheat futures show that the suggested model outperforms previous published models. A numerical example shows the magnitude of pricing errors for option valuation.     

A further note on the optimality of the OLS hedge strategy

This note considers the hedging effectiveness of a dynamic hedge strategy as compared to the conventional OLS strategy. The conditions for the superiority of the OLS strategy are identified. It is argued that these conditions are frequently satisfied and therefore one expects to find the dominance of the OLS strategy over any dynamic strategy in the empirical work. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:308–311, 2008     

Optimal futures heading: Quadratic versus exponential utility functions

Although quadratic and exponential utility functions both lead to mean‐variance expected utility analysis, this study demonstrates that the two approaches produce different optimal futures hedging decisions. Specifically, the deviation between the optimal production level and the optimal futures position is always smaller under the exponential utility framework. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28: 208–211, 2008     

A new information share measure

In this study, we modify the information share (IS) originally proposed by Hasbrouck, J. (1995). The proposed modified information share (MIS) leads to a unique measure of price discovery instead of the upper and lower IS bounds. Performance of MIS is compared with the Hasbrouck IS measure and the Gonzalo–Granger permanent–transitory decomposition (PT/GG)‐based measure using simulations with 1,000 replications applied to the same three examples considered by Hasbrouck, J. (2002). The MIS is found to outperform both Hasbrouck IS measure and PT/GG measure. The empirical application of the MIS to three major stock indices indicates that price discovery takes place mostly in the futures market. Hence, the evidence supports the transaction cost hypothesis as well as the model proposed by Garbade, K. D., and Silber, W. L. (1983). © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:377–395, 2009     

Bad volatility is not always bad: evidence from the commodity markets

ABSTRACT

Using exchange-traded fund (ETF) options data, we examine the predictive power of variance risk premium on returns of four commodities: crude oil, natural gas, gold and silver. We also analyze the predictive power of upside and downside variance risk premiums using a decomposition model conditional on the direction of the underlying market movement. We find that both the undecomposed and decomposed variance risk premiums are able to predict commodity prices. The decomposed variance risk premiums, however, outperform the undecomposed premium. The importance of upside and downside variance risk premiums differs across markets, related to hedging demand. In energy markets, both upside and downside premiums have strong predictive power, while in precious metal markets, only the upside premium is predictive.