Synthetic Controls: A New Approach to Evaluating Interventions

Synthetic control methods are a novel approach to comparative case study research using observational data. Though developed within political science, the methods can potentially be applied to a wide range of evaluation problems in economics, public health, social policy and other disciplines. In the traditional approach, an area in which a new or redesigned service is being implemented is compared with another ‘control’ area (in which there is no change) and statistical adjustment used to account for any differences between areas that might bias the comparison. In the new approach, a synthetic control is derived using data on past trends in all potentially comparable areas, providing a more robust basis for identifying the impact of the service change. Synthetic control methods may be a valuable addition to the range of techniques available for non-randomised evaluations of social, economic and public health interventions. To date there have been few applications in a UK context, and none in Scotland. Published evidence suggests considerable potential to apply synthetic controls to public service innovations at NHS Board, local authority or Community Planning Partnership level, and may widen the range of policy and practice changes that can usefully be evaluated

Evaluability Assessment: A Systematic Approach to Deciding Whether and How to Evaluate Programmes and Policies

Evaluability assessment (EA) is a systematic approach to planning evaluation projects. It involves structured engagement by researchers with stakeholders to clarify intervention goals and how they are expected to be achieved, the development and evaluation of a logic model or theory of change, and provision of advice on whether or not an evaluation can be carried out at reasonable cost, and what methods should be used. To date, EA has been relatively little used in the UK, but it has begun to attract attention as a way of balancing the growing demand for evaluation with the limited resource available. As well as providing a sound basis for making decisions about whether and how to evaluate before resources are committed, EA can improve the translation of research into practice by ensuring that policy-makers and practitioners are involved from the beginning in developing and appraising evaluation options. Two EAs have recently been conducted in Scotland, which provide a model that can be applied to a wide range of interventions, programmes and policies at national, regional and local levels. What Works Scotland is keen to work with Community Planning Partnerships (CPPs) to identify opportunities for EA

Managing direct energy use now and in the future

[Background and Introduction]: Agricultural producers are currently aware of increasing energy costs. This has occurred before the scientific and political debate on climate change has been resolved and a decision made on the best policy instruments to be used to respond. In parallel to this discussion, the on farm assessment of direct energy inputs (i.e. diesel and electricity) enables farmers to react positively to the potential of rising energy costs while contributing to a reduction in greenhouse gasses (GHGs) regardless of the scientific and policy debate surrounding climate change and emissions reduction. Previous work undertaken by the National Centre for Engineering in Agriculture (NCEA) has studied direct on farm energy use involving a number of case study cotton farms to understand the range, costs and contributions of energy use to cotton production and greenhouse gas emissions. The results from this work showed that energy use varies depending on the cropping enterprise and the farming system and that there are significant opportunities to reduce energy and costs. In comparison the greenhouse gas emissions (GHGs) from direct energy use can be similar and in fact greater than the GHGs generated by soil / fertiliser / water interactions. Improving on farm energy use would appear to be as important as improving nitrogen efficiency. A more detailed study undertaken by the NCEA on a large cotton farm in the Gwydir Valley (reference) identified significant reductions in energy resulting from the adoption of reduced tillage systems. The study showed that the adoption of a minimum tillage system had reduced energy costs (and greenhouse emissions) by 12% since 2000 and developing a 'near zero till' system had the potential to reduce this to 24% less than 2000 energy costs. It is evident from this work that there is substantial scope to improve energy use efficiency in cotton production systems, but to enable more growers to identify where they can improve, further development of tools, processes and human capacity is required. In the cropping sector a number of practice changes and technology developments have been, or are being, adopted which can be expected to reduce fuel / energy use or energy use intensity. Examples include minimum / zero tillage, controlled traffic, a range of precision ag technologies, planting of GM crops, some water use efficiency measures and use of legumes in crop rotations. Unfortunately, because the primary driver for the adoption of these practices and technologies has not been energy costs or efficiency, relatively few studies have considered the energy savings or efficiencies associated with them. Within highly mechanised agricultural productions systems such as the Australian Cotton Industry direct energy inputs (i.e. diesel and electricity) represent a major cost to the grower and potentially a significant proportion of the total green house gas (GHG) emissions. Previous studies by Baillie and Chen (2008) have reported significant savings in energy for both a refinement in current practices (i.e. up to 30 % for individual operations) and a change in practice (10 – 20% across the farming system) through energy assessment

Strategies for maximizing sugarcane yield with limited water in the Bundaberg district

Between 1995 and 2003 sugarcane farmers in Bundaberg had access to limited irrigation water. Over this time water allocations were effectively a quarter of the requirements for a fully irrigated crop. In response to this problem irrigation strategies were developed to assist farmers. Field investigations focused on the performance of water winch and furrow irrigation systems, which make up 91 percent of the irrigated area in the district. As most of these application systems have insufficient capacity to meet crop demands, opportunities to schedule irrigations were limited to start up after rain. Improvements in irrigation system performance were found to provide the greatest potential to increase sugarcane yield under conditions of limited water. Investigations identified that irrigation performance could be significantly improved through relatively minor adjustment. Timing of irrigation start up after rain influenced how much water could be applied to the field. Even with relatively low allocations delayed start up strategies could lead to a situation where water was left over at the end of the season

Analysing randomised controlled trials with missing data : Choice of approach affects conclusions

Copyright © 2012 Elsevier Inc. All rights reserved. PMID: 22265924 [PubMed - indexed for MEDLINE]Peer reviewedPostprin

Interbank tiering and money center banks

Interbank markets are tiered rather than flat, in the sense that many banks do not lend to each other directly but through money center banks which act as intermediaries. This paper captures the notion of tiering by designing a core-periphery model and develops a procedure for fitting an empirical network to this model. We find strong evidence of tiering for the German banking system, using bilateral interbank exposures among 1,800 banks. Moreover, bank-specific features, such as bank size, help explain how banks position themselves in the interbank market, suggesting that models with heterogenous banks could help shed light on how financial networks are formed.Interbank market

Selected highlights from the study of mesons

We provide a brief review of recent progress in the study of mesons using QCD's Dyson-Schwinger equations. Along the way we touch on aspects of confinement and dynamical chiral symmetry breaking but in the main focus upon: exact results for pseudoscalar mesons, including aspects of the eta-eta' problem; a realisation that the so-called vacuum condensates are actually an intrinsic, localised property of hadrons; an essentially nonperturbative procedure for constructing a symmetry-preserving Bethe-Salpeter kernel, which has enabled a demonstration that dressed-quarks possess momentum-dependent anomalous chromo- and electromagnetic moments that are large at infrared momenta, and resolution of a longstanding problem in understanding the mass-splitting between rho- and a1-mesons such that they are now readily seen to be parity partners in the meson spectrum; features of electromagnetic form factors connected with charged and neutral pions; and computation and explanation of valence-quark distribution functions in pseudoscalar mesons. We argue that in solving QCD, a constructive feedback between theory and extant and forthcoming experiments will enable constraints to be placed on the infrared behaviour of QCD's beta-function, the nonperturbative quantity at the core of hadron physics.Comment: 28 pages, 15 figures, 2 tables. Version to appear in the Chinese Journal of Physic

Using the literature to quantify the learning curve: a case study

Objective: To assess whether a literature review of a technology can allow a learning curve to be quantified. Methods: The literature for fibreoptic intubation was searched for studies reporting information relevant to the learning curve. The Cochrane Librar y, Medline, Embase and Science Citation index were searched. Studies that reported a procedure time were included. Data were abstracted on the three features of learning: initial level, rate of learning and asymptote level. Random effect meta-analysis was performed. Results: Only 21 studies gave explicit information concerning the previous experience of the operator(s). There were 32 different definitions of procedure time. From 4 studies of fibreoptic nasotracheal intubation, the mean starting level and time for the 10th procedure (95% confidence interval) was estimated to be 133s (113, 153) and 71s (62, 79) respectively. Conclusions: The review approach allowed learning to be quantified for our example technology. Poor and insufficient reporting constrained formal statistical estimation. Standardised reporting of non-drug techniques with adequate learning curve details is needed to inform trial design and costeffectiveness analysis