Confounding and collinearity in regression analysis: a cautionary tale and an alternative procedure,illustrated by studies of British voting behaviour

Quality & Quantity - Many ecological- and individual-level analyses of voting behaviour use multiple regressions with a considerable number of independent variables but few discussions of their...     

Hedonic pricing and the role of stud fees in the market for thoroughbred yearlings in Australia

Using data from one of Australia's largest thoroughbred auction houses, we investigate the price determinants of thoroughbred yearlings sold at auction. We include novel key variables to construct hedonic pricing models and examine the relative role of stud fees compared to the wide range of attributes in the pricing of yearlings. We find that the price effect of stud fees is influenced by the value buyers place on both the characteristics of sires and the characteristics of sire side siblings. The findings imply that the quality of dams a sire has been matched within the breeding market has consequential effects on yearling prices through the sire's stud fee and progeny.     

Are the Best Small Companies the Best Investments?

Previous research finds that large companies previously judged to be excellent growth companies have subsequently been poor investments. We examine small companies selected by Business Week on the basis of multiple criteria used in annual articles featuring highly rated growth companies. We study the investment performance over the three years before eleven annual Business Week publications and the three years after publication. We find positive excess returns in the pre‐publication period, but negative excess returns in the post‐publication period. This reversal in investment performance appears to be due to a mean‐reversion tendency in operating performance, in which the earnings and the past rates of return on capital of such companies subsequently decrease significantly.     

Technological innovation and real investment booms and busts

We investigate why new, high-risk technologies can attract excessive and often unprofitable investment. We develop an equilibrium model in which rational, risk-averse agents overinvest in a risky technology, possibly to the point that its expected return is negative. Overinvestment results from relative wealth concerns which arise endogenously from the imperfect tradability of future endowments. Competition over future consumption leads to an indirect utility for wealth with “keeping up with the Joneses” properties that can induce herding. Because overinvestment increases with the risk of the technology, our model can explain why new, risky technological innovations may promote investment bubbles.     

Asymmetric performance: the market share impact of scale and link alliances in the global auto industry

This study investigates how participating in strategic alliances with rivals affects the relative competitive positions of the partner firms. The paper builds on studies that show significant differences in the outcomes of scale and link alliances. The study argues that the more asymmetric outcomes of link alliances translate into greater changes in the relative market shares of the partner firms, due to unbalanced opportunities for inter‐partner learning and learning by doing. We find support for this argument by examining 135 alliances among competing firms in the global automobile industry, from 1966 to 1995. Copyright © 2004 John Wiley & Sons, Ltd.     

Relationship of direct nursing care hours to DRG and severity of illness

Great variation in nursing resource use is documented within DRGs. Much of this variation may be explained by patient severity of illness. Variance in nursing resource use within DRGs can be reduced by using a severity of illness instrument to score patients.     

New Evidence on the Performance Advantages of Multihospital Systems

This study analyzes the performance effects of proprietary, multihospital systems. It is shown that the organizational structure of these systems may affect the operating costs of member hospitals. Estimating a cost function for Florida hospitals and controlling for other factors, the average costs of HUMANA hospitals are empirically about 17 percent lower, while the costs of other leading chains are about 12 percent lower than not-for-profit institutions. These results contrast with earlier studies that found no such differences. Furthermore, the cost differential that exists between system and non-system hospitals can be largely attributed to technical efficiencies arising from chain ownership.