On quantifying expert opinion about multinomial models that contain covariates

This paper addresses the task of forming a prior distribution to represent expert opinion about a multinomial model that contains covariates. The task has not previously been addressed. We suppose the sampling model is a multinomial logistic regression and represent expert opinion about the regression coefficients by a multivariate normal distribution. This logistic-normal model gives a flexible prior distribution that can capture a broad variety of expert opinion. The challenge is to (i) find meaningful assessment tasks that an expert can perform and which should yield appropriate information to determine the values of parameters in the prior distribution, and (ii) develop theory for determining the parameter values from the assessments. A method is proposed that meets this challenge. The method is implemented in interactive user-friendly software that is freely available. It provides a graphical interface that the expert uses to assess quartiles of sets of proportions and the method determines a mean vector and a positive-definite covariance matrix to represent the expert's opinions. The chosen assessment tasks yield parameter values that satisfy the usual laws of probability without the expert being aware of the constraints this imposes. Special attention is given to feedback that encourages the expert to consider his/her opinions from a different perspective. The method is illustrated in an example that shows its viability and usefulness

The Healthy Steps Study: A randomized controlled trial of a pedometer-based Green Prescription for older adults. Trial protocol

Background: Graded health benefits of physical activity have been demonstrated for the reduction of coronary heart disease, some cancers, and type-2 diabetes, and for injury reduction and improvements in mental health. Older adults are particularly at risk of physical inactivity, and would greatly benefit from successful targeted physical activity interventions. Methods/Design: The Healthy Steps study is a 12-month randomized controlled trial comparing the efficacy of a pedometer-based Green Prescription with the conventional time-based Green Prescription in increasing and maintaining physical activity levels in low-active adults over 65 years of age. The Green Prescription interventions involve a primary care physical activity prescription with 3 follow-up telephone counselling sessions delivered by trained physical activity counsellors over 3 months. Those in the pedometer group received a pedometer and counselling based around increasing steps that can be monitored on the pedometer, while those in the standard Green Prescription group received counselling using time-based goals. Baseline, 3 month (end of intervention), and 12 month measures were assessed in face-to-face home visits with outcomes measures being physical activity (Auckland Heart Study Physical Activity Questionnaire), quality of life (SF-36 and EQ-5D), depressive symptoms (Geriatric Depression Scale), blood pressure, weight status, functional status (gait speed, chair stands, and tandem balance test) and falls and adverse events (self-report). Utilisation of health services was assessed for the economic evaluation carried out alongside this trial. As well, a process evaluation of the interventions and an examination of barriers and motives for physical activity in the sample were conducted. The perceptions of primary care physicians in relation to delivering physical activity counselling were also assessed. Discussion: The findings from the Healthy Steps trial are due in late 2009. If successful in improving physical activity in older adults, the pedometer-based Green Prescription could assist in reducing utilisation of health services and improve cardiovascular health and reduction of risk for a range of non-communicable lifestyles diseases

Effectiveness of influenza vaccine against laboratory-confirmed influenza, in the late 2011-2012 season in Spain, among population targeted for vaccination

Background: In Spain, the influenza vaccine effectiveness (VE) was estimated in the last three seasons using the observational study cycEVA conducted in the frame of the existing Spanish Influenza Sentinel Surveillance System. The objective of the study was to estimate influenza vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza-like illness (ILI) among the target groups for vaccination in Spain in the 2011-2012 season. We also studied influenza VE in the early (weeks 52/2011-7/2012) and late (weeks 8-14/2012) phases of the epidemic and according to time since vaccination. Methods: Medically attended patients with ILI were systematically swabbed to collect information on exposure, laboratory outcome and confounding factors. Patients belonging to target groups for vaccination and who were swabbed 4 months, respectively, since vaccination. A decrease in VE with time since vaccination was only observed in individuals aged ≥ 65 years. Regarding the phase of the season, decreasing point estimates were only observed in the early phase, whereas very low or null estimates were obtained in the late phase for the shortest time interval. Conclusions: The 2011-2012 influenza vaccine showed a low-to-moderate protective effect against medically attended, laboratory-confirmed influenza in the target groups for vaccination, in a late season and with a limited match between the vaccine and circulating strains. The suggested decrease in influenza VE with time since vaccination was mostly observed in the elderly population. The decreasing protective effect of the vaccine in the late part of the season could be related to waning vaccine protection because no viral changes were identified throughout the season

Shaping cash transfer impacts through “soft-conditions”: evidence from Lesotho

Cash transfer programmes have been shown to have positive effects on a variety of outcomes. While much of the literature focuses on the role of conditionality in achieving desired impact, this paper focuses on the role of ‘soft conditionality’ implemented through both ‘labelling’ and ‘messaging’ in evaluating the impact of the Child Grants Program in Lesotho, an unconditional cash transfer programme targeting poor households with orphans and vulnerable children. Beneficiary households received a clear message that the transfer should be spent on the interest and needs of children. Our findings suggest that ‘soft conditionality’ does play a role in increasing expenditure for children, especially on education, clothing and footwear. Results indicate in fact that transfer income is spent differently from general income as it exerts both an income and a substitution effect. This behavioural change is confirmed by comparing the ex-ante expected behaviours with the ex-post actual response to the programme. We find that for expenditure categories linked to the well-being of children the expost response was much higher than the ex-ante expected behaviour

A Nutrition-Sensitive Agroecology Intervention in Rural Tanzania Increases Children's Dietary Diversity and Household Food Security But Does Not Change Child Anthropometry: Results from a Cluster-Randomized Trial.

This research article published by Oxford University Press, 2021Background There are urgent calls for the transformation of agriculture and food systems to address human and planetary health issues. Nutrition-sensitive agriculture and agroecology promise interconnected solutions to these challenges, but evidence of their impact has been limited. Objectives In a cluster-randomized trial (NCT02761876), we examined whether a nutrition-sensitive agroecology intervention in rural Tanzania could improve children's dietary diversity. Secondary outcomes were food insecurity and child anthropometry. We also posited that such an intervention would improve sustainable agricultural practices (e.g., agrobiodiversity, intercropping), women's empowerment (e.g., participation in decision making, time use), and women's well-being (e.g., dietary diversity, depression). Methods Food-insecure smallholder farmers with children aged <1 y from 20 villages in Singida, Tanzania, were invited to participate. Villages were paired and publicly randomized; control villages received the intervention after 2 y. One man and 1 woman “mentor farmer” were elected from each intervention village to lead their peers in agroecological learning on topics including legume intensification, nutrition, and women's empowerment. Impact was estimated using longitudinal difference-in-differences fixed-effects regression analyses. Results A total of 591 households (intervention: n = 296; control: n = 295) were enrolled; 90.0% were retained to study end. After 2 growing seasons, the intervention improved children's dietary diversity score by 0.57 food groups (out of 7; P < 0.01), and the percentage of children achieving minimum dietary diversity (≥4 food groups) increased by 9.9 percentage points during the postharvest season. The intervention significantly reduced household food insecurity but had no significant impact on child anthropometry. The intervention also improved a range of sustainable agriculture, women's empowerment, and women's well-being outcomes. Conclusions The magnitude of the intervention's impacts was similar to or larger than that of other nutrition-sensitive interventions that provided more substantial inputs but were not agroecologically focused. These data suggest the untapped potential for nutrition-sensitive agroecological approaches to achieve human health while promoting sustainable agricultural practices