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This study examines the relationships between the employability and criminality of white and black male teenagers. A disequilibrium model of employment and crime is formulated and estimated as a simultaneous probit equation system. Our results show that black teenagers who are employed engage in fewer criminal activities. Thus, it appears that blacks view employment and crime as alternative income-generating activities. On the other hand, the criminal behavior of white male teenagers is unaffected by their employment status. The evidence that we provide indicates that whites tend to use employment as a cover for crime or to moonlight in crime. The differences in the behaviors of whites and blacks can be explained, in part, by different legitimate opportunity structures for whites and blacks. One of the more important policy implications is that job opportunities targeted to high risk, black teenage populations will have the additional beneficial effect of reducing crime rates.

We look at conventional methods for removing endogeneity bias in regression models, including the linear model and the probit model. It is known that the usual Heckman two-step procedure should not be used in the probit model: from a theoretical perspective, it is unsatisfactory, and likelihood methods are superior. However, serious numerical problems occur when standard software packages try to maximize the biprobit likelihood function, even if the number of covariates is small. We draw conclusions for statistical practice. Finally, we prove the conditions under which parameters in the model are identifiable. The conditions for identification are delicate; we believe these results are new.

As a contribution to the theorization of the planning process, this article gives a brief account of the probit model and its applications to Hong Kong; a review of the literature on the use of development control data in planning research; advances the argument for the use of statistical methods that do not operate on aggregate sampling data; and demonstrates the applicability of the probit model in development control studies. Possible applications discussed are the identification of factors for predicting success in planning applications, measurement of zone separation, assessment of the effectiveness of the planning system in tackling externalities, verification of economic theories of the behaviour of planning authorities and evaluation of public participation.