A play-the-winner-type urn design with reduced variability

We propose a new adaptive allocation rule, the drop-the-loser, that randomizes subjects in the course of a trial comparing treatments with dichotomous outcomes. The rule tends to assign more patients to better treatments with the same limiting proportion as the randomized play-the-winner rule. The new design has significantly less variable allocation proportion than the randomized play-the-winner rule. Decrease in variability translates into a gain in statistical power. For some values of success probabilities the drop-the-loser rule has a double advantage over conventional equal allocation in that it has better power and assigns more subjects to the better treatment. Acknowledgments. I thank Stephen Durham, the associate editor, and the referees for their helpful suggestions.     

Earnings management and abnormal returns: Evidence from the 1970–1972 Price Control Regulations

We examine the association between abnormal returns and earnings management in the context of price control regulations to test the construct validity of the earnings management model. Abnormal returns are used as a market–based measure, and discretionary accruals are employed to measure earnings management. Our results support the hypotheses that (1) price control regulations affect firms' security prices negatively, (2) firms make income–decreasing discretionary accruals to increase the likelihood of price increase approval, and (3) firms that are affected most negatively by the regulations manage earnings more aggressively. We conclude that the earnings management model we use in this study is capable of predicting opportunistic discretionary accruals.     

Moderation by goal commitment of the feedback–performance relationship: Theoretical explanation and preliminary study

This paper presents goal commitment as one stage of a multidimensional goal striving process that affects feedback acquisition, processing, and use during the achievement of performance goals. Specifically, this paper argues that higher goal commitment leads to more effective acquisition, processing, and use of feedback that in turn fosters higher performance than does lower goal commitment. To provide a preliminary test of this proposition, data from an earlier field study conducted by the author and colleagues [J. Occup. Organ. Psychol. 72 (1999) 107] were used to examine the moderating effects of goal commitment on the relationship between perceived task feedback amount and work performance of 196 rehabilitation counselors. Results were consistent with this proposed interaction, as perceived task feedback amount had a positive linear relationship with work performance for higher goal commitment rehabilitation counselors and a negative linear relationship with performance for lower goal commitment counselors. The discussion urges researchers to broaden their views of goal commitment beyond the goal difficulty–performance relationship and to devote more attention to moderators of the feedback–performance relationship. Directions for future research and practical implications are also discussed.     

An Examination of the Interaction Between Modelling and Its Relationship with Construction Kits: Lessons from the Past and for the Future

Construction kits have played a significant part in nurturing the growth and development of the minds and manipulation-based skills of children (and adults) in formal and non-formal education settings. These kits have origins rooted in the representation of the built world and now have a diversity of form and function, including technical versions with moving parts. This article examines some of the historically based ideas that lie behind the role that kits may have in terms of physical modelling. The article traces the transformation of kits from simple bricks and blocks into more complicated pieces for space-filling and achieving the transfer of forces and motion. This transformation occurred during the Victorian era when the influence of the ideas of educationalists and, perhaps rather strangely, exponents of early aviation, played major roles in determining the diversity of forms of construction kit and modelled possibilities that are now to be seen in classrooms and homes. The article ends with a review of some of the lessons from the past and present that will need to be considered in relation to concrete modelling in schools for the future. This revised version was published online in July 2006 with corrections to the Cover Date.