Faster Implied Volatilities via the Implicit Function Theorem

We present a faster, more accurate technique for estimating implied volatility using the standard partial derivatives of the Black‐Scholes option‐pricing formula. Beside Newton‐Raphson and slower approximation methods, this technique is the first to provide an error tolerance, which is essential for practical application. All existing noniterative approximation methods do not provide error tolerances and have the potential for large errors.     

Situational and trait interactions among goal orientations

Regulatory focus theory has been used to describe and explain a wide range of consumer responses. This goal orientation has been examined both as a chronic difference and a situational variable. Yet, it is unclear how a situational manipulation interacts with the individual??s chronic goal orientation. The present research investigates the potential for interactions and suggests that typical outcomes of regulatory focus are likely to emerge more clearly under circumstances in which promotion focus is manipulated. The studies demonstrate asymmetric effects in the interactions of chronic and situational manipulations of regulatory focus using different manipulations and outcome variables. The implications of these findings are significant for any research involving the manipulation of variables that can also be considered as chronic tendencies.     

Persistence and Change at the Top of the IT Sector

We use the DATAMATION index of the top 50 domestic IT companies (1975–1995) to track persistence and change at the top of the sector. The trends that we uncover are increasing instability, rejuvenation (declining average age of entrants coupled with increasing average age of quitters), democratization (diminishing revenue inequality at the top) and growing supply‐side intertwining of sub‐sectors and industries within IT due to diversification by long‐term survivors.     

Quasitransitive social preference: why some very large coalitions have very little power

Summary. If only the strict part of social preference is required to be transitive then Independence of Irrelevant Alternatives implies that there is a coalition containing all but one individual that cannot force x to be socially ranked above y for at least half of the pairs of alternatives (x,y). Received: August 29, 1996; revised version: March 24, 1997     

当中国向世界展示设计主导而非研发主导的创新时

增长市场的关键不在于对科技研发主导的产品进行逐步的改善和优化，真正的业务增长来自于对用户的理解：揭示消费者未被满足的，未被提出的需求，然后满足这些需求     

Strategic and Business Planning Practices of Fast Growth Family Firms

Fast-growth family firms were surveyed about their business and strategic planning practices. Of the 65 fast-growth family firms surveyed, the majority prepare written formal plans. The business plans are in sufficient detail to enable the business to tie planning to actual performance and to adjust management compensation accordingly. The majority of the firms regularly share information with employees regarding comparisons between actual company performance results and goals or planned performance. Further, the majority of the firms describe their business strategy as a high quality producer strategy rather than as a low-cost or time-based strategy. Further, when bringing new products to market, these fast-growth family firms adopt a first mover or early follower strategy. Implications of these findings for growth-oriented family firms are presented.