How useful are recoveries of North American passerines for survival analyses?

Of 17 000 000 passerines ringed in North America from 1955 to 1984, only 0.4% were ever recovered. Only 62 species had more than 100 recoveries, of which only 26 had more than 500 recoveries. Preliminary analyses using stochastic recovery models for four of the species with more than 500 recoveries suggest estimates of mean annual adult survival can be fairly precise (CV < 4%), but estimates of immature survival are much less precise (CV > 8%). Comparable estimates may be possible for other species with more than 100 recoveries, depending on the temporal and geographic distribution of ringings and recoveries. Further analyses are required to determine whether these estimates may be biased by heterogeneity in survival or recovery rates.     

Maintaining strategic momentum: The CEO''s agenda

How does the chief executive of a large complex organization maintain strategic momentum? This represents a great challenge when there are no obvious external threats, and no obvious reasons for having a concerted action. Floris Maljers, Charles Baden-Fuller and Frans van den Bosch explore the inherent tensions which exist between stability and change. Change is necessary to maintain success, but too much change is disastrous. The authors argue that there are several possible solutions to this paradox, including that of generating periods of intense activity followed by periods of comparative stability and incremental improvement. Using the introspection of one of the CEOs of Unilever, who held office from 1984 to 1994, the authors examine how these tensions were played out and resolved.     

Life Cycle Changes and Criminal Propensity*

The relationship between age and self-reported propensity toward criminal behavior is investigated among a large survey sample, and an attempt is made to explain the observed variations. Results indicate a clear negative relationship between age and criminal propensity which is in part attributed to generational differences and partly to life cycle changes. Efforts to account for the association show this relationship to be exceptionally stable and resistant to explanation. Nevertheless analysis suggests complex interactions among several variables as the appropriate explanation.     

The Effect of Social Characteristics on Juvenile Court Dispositions*

Of the growing number of criticisms directed at various facets of the juvenile justice system, none is more common than the contention that the informality of the juvenile court encourages discrimination. The purpose of this study. which is based on data obtained from a sample of 1,522 official court records, is to provide an assessment of the impact of a variety of social background, demographic, and offense-related variables on the severity of sanctions imposed by juvenile court judges in one southeastern metropolitan jurisdiction. The findings show that the extra-legal variables which were considered have an effect on case disposition even when offense seriousness and prior records of delinquency are held constant.     

Linking organizational effectiveness and environmental change

Advisors on strategic planning often give two separate pieces of advice to managers: first, managers must interact with rather than react to the external environment. That is, they should be proactive, not reactive. Second, the organizational effectiveness must be improved. However, seldom is any linkage established between these two pieces of advice. The first premise is primarily an external view, and the second is an internal view. If these two views are not linked, the results may range from slightly below optimum to bankruptcy. The purpose of this article is to show how these two views can be linked.     

Some computational problems related to multinomial trials

Efficient numerical algorithms are developed to evaluate several probabilities related to multinomial trials.In the first part of the paper, the probability distribution of the number of trials until the alternatives j, j = 1,… m, have occurred at least i_j times is computed. The multinomial trials involve the m alternatives l,…, m, with positive probabilities P_l-P_m of occurrence. In the second part, several aspects of a multinomial subset selection problem, discussed by S. S. Gupta and K. Nagel, are investigated.