Snapshot samples

We consider a coverage model where an initial event that occurs at some point in time triggers an activity of random duration that leads to some subsequent event. A snapshot sample is constructed at a fixed point in chronological time either by sampling only subjects where the initial event has occurred but the subsequent event has yet to occur (active subjects), or by sampling only subjects where both the initial and subsequent events have occurred (inactive subjects). The biases inherent in snapshot sampling can be neatly characterized by the properties of two random variables: the history (defined as the time the initial event occurs as measured into the past from the chronological point of sampling), and the active time (defined as the length of time between the initial and subsequent events). Though snapshot samples are biased, recognizing the biases enables correct inferences to be drawn from snapshot-sampled data. Considering only the case where and are independent random variables, this paper presents the probability models associated with snapshot sampling, demonstrates the problems that can occur, offers procedures for overcoming these problems, and applies the methods to interesting data sets.     

From edgeworth to fisher to vickrey: A comment on Michael J. Boskin's Vickrey lecture

Irving Fisher has been overlooked as an influence on William Vickrey's work on taxation and as a link between Edgeworth and Vickrey. Vickrey was Fisher's last and greatest student.     

A MULTINOMIAL APPROXIMATION FOR AMERICAN OPTION PRICES IN LÉVY PROCESS MODELS

This paper gives a tree-based method for pricing American options in models where the stock price follows a general exponential Lévy process. A multinomial model for approximating the stock price process, which can be viewed as generalizing the binomial model of Cox, Ross, and Rubinstein (1979) for geometric Brownian motion, is developed. Under mild conditions, it is proved that the stock price process and the prices of American-type options on the stock, calculated from the multinomial model, converge to the corresponding prices under the continuous time Lévy process model. Explicit illustrations are given for the variance gamma model and the normal inverse Gaussian process when the option is an American put, but the procedure is applicable to a much wider class of derivatives including some path-dependent options. Our approach overcomes some practical difficulties that have previously been encountered when the Lévy process has infinite activity.     

Analysis of Beef Producers' Risk Management Perceptions and Desire for Further Risk Management Education

Beef cattle producers were surveyed in Texas and Nebraska to investigate perceptions of sources of risk, the effectiveness of risk management strategies, and interest in further risk management education, particularly production risk, using probit analysis. Important decision variables identified are age, prior use of risk management tools, previous attendances of risk management education, and risk aversion. Severe drought and cattle price variability are identified as primary risk factors with potential to affect farm income. Extremely cold weather and disease are of less importance. Understocking pasture and storing hay are perceived most effective as risk management options.     

Estimating the effectiveness of extension information systems using farm trials and subjective probabilities

A method of combining survey data and Dairy Herd Improvement Association (DHIA) records to achieve low cost farm trials is presented. Farm trials and surveys of current practices and production responses are useful to identify yield gaps between expectations predicted from experimental findings and actual field results. Different management schemes can be ranked using subjective probabilities and stochastic dominance to enhance successful implementation of research findings and to increase the feedback between researchers, extension workers, and producers. A survey of current masitis control practices and expected milk yield response is the example. Combining survey results with DHIA records allowed estimating the relationship between somatic cell counts (SCC) and milk yield. Eliciting beliefs about the relationship between SCC and milk yield showed that producers agreed with predictions from the statistical model. Subjective probabilities about SCC and mastitis control practices showed that our sample of experts and producers consistently ranked the different practices but extension agents had no consensus about the the most or least effective ones.     

WORLD OUTLOOK

Events in the Gulf have finally brought an end to the world economic boom of the last eight years. The oil price shock itself is only partly responsible for the downturn. The previous tightening of monetary policy in the face of inflationary pressures and the end of a rapid period of credit and asset price expansion had severely weakened the ability of some economies to respond to the shock. This is reflected in the diversity of response, most obviously in the United States where Fed fine tuning and the credit crunch have already weakened the economy. The rise in oil prices has led to a sudden collapse in consumer confidence and a swift cutback in output. Although we do not expect the recession to be deep, the financial problems will delay recovery. The Japanese economy was already in financial difficulties before the shock, although the real economy was stronger and here we expect a sharp deceleration from almost 6 per cent growth last year to around 3.5 per cent. In contrast the German economy, partly shielded by the substantial appreciation of the DM over the last year, has been affected less by the oil price shock and we expect the consumer and investment boom to continue this year as the economies merge. This provides a welcome boost to other European economies.     

Risk and the miller equilibrium: Capital structure choice with risk-averse investors

Merton Miller's (1977) tax model of equilibrium capital structure choice results in capital structure irrelevance and the existence of tax clienteles, assuming the restrictive case of risk-neutrality. Relaxation of the assumption of risk-neutrality in Miller's tax framework, allowing utility-maximizing risk-averse investors, indicates that capital structure irrelevance continues to hold under reasonable assumptions about utility. Evaluation of resulting tax clienteles shows that marginal tax rates do not restrict investors from investing in equities but do affect the tax status of purchased bonds.     

INDEPENDENT EXPERT'S REPORTS IN TAKEOVER BIDS

This paper reports an empirical examination of independent expert reports in takeover bids using the 170 reports that were issued in the 364 cash-based bids that occurred between January 1988 and December 1991. It was found that bid premia offered in takeover bids where an expert's report was issued were not significantly lower than bid premia in other bids. This may be attributable to independent experts acting as a countervailing influence on bidders holding a superior pre-bid bargaining position. Next, some dimensions of the “fair and reasonable” criterion that experts are required to use are examined. These are the single-test and dual-test interpretations of the phrase, the relation between offer price, market price and the expert's valuation of the target, the cost and length of expert's reports and, finally, the influence an expert has on the outcome of a bid.