Technological forecasting as a guide for managerial planning

The author discusses the limitations of statistical forecasting as a guide to managerial planning, with specific reference to technological and market changes in the glass industry. He advocates the use of a Forecast Adjustment Matrix as a framework for identifying marketing and technological factors which might produce significant deviations from established trends. Finally, he suggests that the analysis and adjustment of technological and market trends should be made periodically. The whole technological forecasting operation should be formalized and it should be made the specific responsibility of one organizational unit within the company.     

Adolescent Women's Recommendations for Enhanced Parent-Adolescent Communication About Sexual Behavior

Family communication about adolescent sexual health and behavior promotes adolescent health and family connectedness. However, few studies seek the perspective of adolescents regarding their recommended strategies for family communication. Findings of a survey of female adolescent family planning patients (n = 249) indicated adolescent recommendations for better family communication included treat teen as an equal, 63%; increase parental knowledge about lifestyle and peer pressures, 61%, and improve parental listening skills, 61%. There were no statistically significant differences according to age, pregnancy history, or school enrollment status for suggested strategies for improved communication with parents. Sexually active adolescent daughters expressed interest in maintaining family connectedness and support with increased time for family activities as well as increased quality and quantity of dialogue between the adolescent girl and her parents.     

An evaluation of collaborative interventions to improve chronic illness care. Framework and study design

The author's dual-purpose evaluation assesses the effectiveness of formal collaboratives in stimulating organizational changes to improve chronic illness care (the chronic care model or CCM). Intervention and comparison sites are compared before and after introduction of the CCM. Multiple data sources are used to measure the degree of implementation, patient-level processes and outcomes, and organizational and team factors associated with success. Despite challenges in timely recruitment of sites and patients, data collection on 37 participating organizations, 22 control sites, and more than 4,000 patients with diabetes, congestive heart failure, asthma, or depression is nearing completion. When analyzed, these data will shed new light on the effectiveness of collaborative improvement methods and the CCM.     

Comparisons of Test Statistics Arising from Marginal Analyses of Multivariate Survival Data

We investigate the properties of several statistical tests for comparing treatment groups with respect to multivariate survival data, based on the marginal analysis approach introduced by Wei, Lin and Weissfeld [Regression Analysis of multivariate incomplete failure time data by modelling marginal distributians, JASA vol. 84 pp. 1065–1073]. We consider two types of directional tests, based on a constrained maximization and on linear combinations of the unconstrained maximizer of the working likelihood function, and the omnibus test arising from the same working likelihood. The directional tests are members of a larger class of tests, from which an asymptotically optimal test can be found. We compare the asymptotic powers of the tests under general contiguous alternatives for a variety of settings, and also consider the choice of the number of survival times to include in the multivariate outcome. We illustrate the results with simulations and with the results from a clinical trial examining recurring opportunistic infections in persons with HIV.     

Comparative Potency Method for Cancer Risk Assessment: Application to Diesel Particulate Emissions1

An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m³ inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10^?4, 3.6 × 10^?4, and 2.2 × 10^?6 per μg particulate organics per m³ air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10^?4. The unit lung cancer risks for the other, less potent motor-vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m³ for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10^?4 to 0.60 × 10^?4; that for the heavy-duty diesel engine was 0.02 × 10^?4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions.