D s -optimal designs for Kozak's tree taper model

In this work, we study D s -optimal design for Kozak's tree taper model. The approximate D s -optimal designs are found invariant to tree size and hence create a ground to construct a general replication-free D s -optimal design. Even though the designs are found not to be dependent on the parameter value p of the Kozak's model, they are sensitive to the s �1 subset parameter vector values of the model. The 12 points replication-free design (with 91% efficiency) suggested in this study is believed to reduce cost and time for data collection and more importantly to precisely estimate the subset parameters of interest.

Association between childhood community safety interventions and hospital injury records: a multilevel study

Study objective: To study municipal variations in children's injury risk and to assess the impact of safety promotion measures in general municipal, preschool, school, and leisure activity settings, on injury outcome. Design: A cohort study based on individual data on children's consumption of hospital care as a result of injury, the age and sex of each child, and socioeconomic data on each child's mother. Municipal characteristics—that is, population density and municipal safety measures—were also used. Connections between individual and community level determinants were analysed with multilevel logistic regression. Setting: Twenty five municipalities in Stockholm County in Sweden were studied. Participants: Children between 1 and 15 years old in 25 municipalities in Stockholm County, identified in the Total Population Register in Sweden. The study base included 1 055 179 person years. Main results: Municipality injury rates varied between 3.84–7.69 per 1000 person years among 1–6 year olds and, between 0.86–6.18 among 7–15 year olds. Implementation of multiple safety measures in a municipality had a significant effect on the risk of injury for preschool children. In municipalities that implemented few safety measures, the risk of injury was 33% higher than in municipalities that implemented many. A similar effect, though insignificant, was observed in the school aged children. Conclusions: This study shows that how municipalities organise their safety activities affect injury rates. Sweden has a comparatively low injury rate and thus, in a European perspective, there is an obvious potential for municipal safety efforts

Optimal design in average for inference in generalized linear models

D A -Optimality, design of experiment, design weights, factorial experiments, Generalized Linear Model, optimal design in average,