The effects of group decision-making process and problem-situation complexity on implementation attempts

The effects of group problem-solving method and problem-situation complexity on attempts at implementing group solutions were investigated in a laboratory-field setting. Group members were supervisory nurses from various organizations, who were randomly assigned to three groups in a balanced research design which included three group decision-making processes and three levels of problem-situation complexity in implementation. The dependent variable was the number of attempts at implementing group-derived solutions in home organizations. The results showed that structure in group decision-making processes led to increased rates of implementation attempts at all levels of problem-situation complexity. There was a significant complexity-by-process interaction effect among the decision-making processes, which supports the conclusion that the type of group decision-making process and the problem-situation complexity should be considered in order to optimize the number of implementation attempts.g     

A child health production function estimated from longitudinal data. Cebu Study Team

Collaborating researchers used a multi equation model to analyze 3080 mother-infant pairs living on the island of Cebu in the central Philippines and to estimate a child health production function. The econometric methods used eliminated obstacles such as heterogeneity and endogeneity of significant explanatory factors. They also maximized the longitudinal quality of the data. The results showed that morbidity in 1 period reduced infant weight in following periods. For example, diarrhea and febrile respiratory infection reduced growth in the time period following the illnesses. Further effects of some contributing factors were great near birth not diminished with age. For example, breast feeding promoted growth and protected against infection, especially diarrhea and febrile respiratory infection, more substantially near birth than it did later. Further, in urban areas, preventive health care positively affected growth independently of its indirect influence on reducing respiratory infection. Yet it had little effect on diarrhea. Diarrhea had a strong adverse effect on growth. Exposure of the infant to enteric pathogens had the greatest influence on production of diarrhea. In urban areas, exposure included water supply contamination, exposure to feces, a more pathogenic diet, and community crowding. In rural areas, however, exposure included community crowding and increased rainfall which presumably washed feces into the water supply. Household crowding in both urban and rural areas and irritation from smoke in urban areas only tended to bring about febrile respiratory infection.     

Stability and agreement criteria for the termination of Delphi studies

This paper addresses the question of the methodology of testing for stability between successive Delphi rounds and the necessity of doing so prior to the analysis of the level or type of consensus. Following a discussion of a hierarchical set of a criteria for determining the termination of such studies, the paper reviews some of the more common treatments of the subject in the literature. It is finally proposed that a χ² test be used to test the stability of responses between rounds. The method is demonstrated by a numerical example.     

A note on the extension of tables for the Friedman statistic

Abstract  The tables for the Friedman rank-test arc extended using a sampling method. A table is given for the traditional significance levels .01, .025, .05 and .10 for number of blocks equal to 7 and 8 and for treatments of size 6 and 7. A brief discussion of available tables is also included along with an example of an application.     

Exceptional Convergence of the Sample Variance

The case is investigated when Hoeffding's one sample U–statistic theorem for the sample variance S² is not applicable. It is shown that this occurs only when the parent distribution is the two–point distribution with jumps of equal magnitude. For this exceptional case the standardised S² is shown to converge in distribution to (1 – V )√2, where V has chi–square distribution with one degree of freedom.     

Testing equality of variances in the analysis of repeated measurements

The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.
The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies.     

Ratings and confirmation

We present a formalism which makes explicit and precise the confirming effect of multiple observers and repeated trials on composite ratings, considering the relevant subjective inputs.     

Analysis of arrest rates for trends in criminality

During the 1960s, the United States experienced a substantial increase in crime with the rates of reported crime more than doubling. It has been postulated that the increase in the proportion of young adults in the population which also occurred during the Sixties is a primary factor in the increase in crime. In this paper, we attempt to explore this question by partitioning the recent increases in rates between an increasing crime-committing propensity for various demographic groups on one hand, and a changing demographic mix to the other. We do this by analyzing arrest rates by demographic group over time. However, since arrest rates are a complex function of both criminality and police activity, a model is developed which attempts to distinguish between these phenomena. The model is estimated using data on age, race, and sex-specific arrest rates for Pittsburgh residents over the period 1967–1972. The results of the analysis suggest that there has been no significant increase in criminality for men in the Pittsburgh population, while there is some evidence of increased criminality for women. However, this increase may reflect an increased willingness of the police to arrest women. We hesitate to generalize our conclusions too widely from the experience of a single urban center. Additional analysis, using the model developed here, of arrest rates from other cities or regions would do much to illuminate this very significant issue.