Estimating the Size of a Criminal Population from Police Records Using the Truncated Poisson Regression Model

The truncated Poisson regression model is used to arrive at point and interval estimates of the size of two offender populations, i.e. drunk drivers and persons who illegally possess firearms. The dependent capture–recapture variables are constructed from Dutch police records and are counts of individual arrests for both violations. The population size estimates are derived assuming that each count is a realization of a Poisson distribution, and that the Poisson parameters are related to covariates through the truncated Poisson regression model. These assumptions are discussed in detail, and the tenability of the second assumption is assessed by evaluating the marginal residuals and performing tests on overdispersion. For the firearms example, the second assumption seems to hold well, but for the drunk drivers example there is some overdispersion. It is concluded that the method is useful, provided it is used with care.     

Multiple Imputation in Multivariate Problems When the Imputation and Analysis Models Differ

Bayesian multiple imputation (MI) has become a highly useful paradigm for handling missing values in many settings. In this paper, I compare Bayesian MI with other methods – maximum likelihood, in particular—and point out some of its unique features. One key aspect of MI, the separation of the imputation phase from the analysis phase, can be advantageous in settings where the models underlying the two phases do not agree.     

DETERMINANTS OF GOODWILL AMORTIZATION PERIOD

This study investigates whether economic consequences have an effect on the length of the period over which goodwill is amortized. It finds that there is a significant relationship between the size of the firm and the length of the amortization period. It also finds, when the only firms included in the sample are those reporting debt covenant restrictions dependent in part on goodwill accounting, evidence that the length of the amortization period for goodwill is related to the firm's leverage.     

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.     

Competition and structural change in Eastern Europe

Widely publicized reform programs for East Europe which emphasize rapid privatization are questioned on the grounds that structural changes to assure workable competition take precedence and will take years. A mix of deconcentrated state, cooperative, worker-owned, private, and foreignowned business can be workable. Import competition and antitrust legislation have auxiliary roles.     

FIRST-MOVER ADVANTAGE: THE OPPORTUNITY CURVE

A model depicting first-mover dynamics is proposed wherein certain types of strategic barriers activated by the first-mover strategy figure prominently in preserving benefits in the time dimension. Strategic barriers conferring singularity (i.e. one-time benefit) are considered to be the most effective preservers of first-mover advantage. the theoretical model is tested empirically in a study of six major industries. Benefits operationalized as industry share and profit share were found to decline consistently with industry age according to an exponential function designated the opportunity curve.     

Development and the mystification of ‘cultural factors’: One destiny: Our common future in Africa,by A S van Niekerk

In One destiny: Our common future in Africa the author relates, in popular fashion, a series of incidents which convinced him that the basic difference between black and white in South Africa is cultural deep‐seated and the cause of underdevelopment and conflict He develops a circular argument in which world‐view is taken as the root of perceptions, values and activities. The effects of experience and economic and political factors are given secondary importance. This argument cannot accommodate social change and differentiation, and the author tends to concentrate on perceptions and events which he finds morally unacceptable. He gives an unbalanced assessment and an ethnocentric interpretation of African life. Possible reasons for this type of argument are explored and an alternative which takes its departure from the interaction between experience and perception is offered     

CAN INEFFICIENT TRADERS CREATE VALUE?

I examine the aggregate expected profit generated by informed traders of diverse ability in a competitive market. I assume that efficient traders get perfect information on asset values whereas inefficient traders get noisy information. In the presence of order size restrictions, I show that the aggregate expected profit generated by efficient and inefficient traders together can be higher than that generated by efficient traders alone. Thus, inefficient traders can create value in a constrained trading environment.