A randomized trial to assess the effectiveness of an infant home safety programme

The aim of this study was to test an intervention aimed at addressing the risk of injury in infants 2 - 12 months of age. A non-blinded, randomized controlled trial was conducted, whereby parents were randomly assigned to either a control or one of two intervention groups. Parents completed questionnaires regarding safety behaviours and injuries at the 2 (baseline), 6 and 12 month immunization visit at the community health unit. During the 2 month visit to the health unit, the two intervention groups received a home safety kit containing nine items, an instructional brochure and a risk assessment checklist. Subjects randomized to the safety kit plus home visit group also received a standardized home visit from a community health nurse. Two of the 14 parental safety behaviours showed a significant increase in use among parents in the intervention groups. Neither of the interventions was associated with a reduction in parent-reported injuries among children. It was concluded that home visitation may provide a beneficial adjunct to the provision of safety devices and may increase use by parents.     

Exact linear rank tests for two‐sample equivalence problems with continuous data

The present paper introduces a methodology for the semiparametric or non‐parametric two‐sample equivalence problem when the effects are specified by statistical functionals. The mean relative risk functional of two populations is given by the average of the time‐dependent risk. This functional is a meaningful non‐parametric quantity, which is invariant under strictly monotone transformations of the data. In the case of proportional hazard models, the functional determines just the proportional hazard risk factor. It is shown that an equivalence test of the type of the two‐sample Savage rank test is appropriate for this functional. Under proportional hazards, this test can be carried out as an exact level α test. It also works quite well under other semiparametric models. Similar results are presented for a Wilcoxon rank‐sum test for equivalence based on the Mann–Whitney functional given by the relative treatment effect.     

Diversity of incentives for private forest landowners: An assessment of programs in Indiana, USA

 Many government and private programs provide incentives for non-industrial private forest (NIPF) owners. Due to the complexity of this web of programs, the incentives of the programs are unclear. We focus on four specific programs that represent different rule structures—a federal cost-share program, a state tax incentive program, a nationwide private stewardship program, and a local private conservation organization. We perform institutional analysis of the formal and informal rules of the programs based on literature review, discussions with officers, and formal guidelines of the programs. We classify different types of rule structures, and explain them in relation to goals and organizational structures of the programs.     

Will It Spread or Not? The Effects of Social Influences and Network Topology on Innovation Diffusion

Innovation diffusion theory suggests that consumers differ concerning the number of contacts they have and the degree and the direction to which social influences determine their choice to adopt. To test the impacts of these factors on innovation diffusion, in particular the occurrence of hits and flops, a new agent‐based model for innovation diffusion is introduced. This model departs from existing percolation models by using more realistic agents (both individual preferences and social influence) and more realistic networks (scale free with cost constraints). Furthermore, it allows consumers to weight the links they have, and it allows links to be directional. In this way this agent‐based model tests the effect of VIPs who can have a relatively large impact on many consumers. Results indicate that markets with high social influence are more uncertain concerning the final success of the innovation and that it is more difficult for the innovation to take off. As consumers affect each other to adopt or not at the beginning of the diffusion, the new product has more difficulties to reach the critical mass that is necessary for the product to take off. In addition, results of the simulation experiments show under which conditions highly connected agents (VIPs) determine the final diffusion of the innovation. Although hubs are present in almost any network of consumers, their roles and their effects in different markets can be very different. Using a scale‐free network with a cut‐off parameter for the maximum number of connections a hub can have, the simulation results show that when hubs have limits to the maximum number of connections the innovation diffusion is severely hampered, and it becomes much more uncertain. However, it is found that the effect of VIPs on the diffusion curve is often overestimated. In fact when the influence of VIPs on the decision making of the consumers is strengthened compared with the influence of normal friends, the diffusion of the innovation is not substantially facilitated. It can be concluded that the importance of VIPs resides in their capacity to inform many consumers and not in a stronger persuasive power.