Decision support for risk prioritisation of environmental health hazards in a UK city

Background There is increasing appreciation of the proportion of the health burden that is attributed to modifiable population exposure to environmental health hazards. To manage this avoidable burden in the United Kingdom (UK), government policies and interventions are implemented. In practice, this procedure is interdisciplinary in action and multi-dimensional in context. Here, we demonstrate how Multi Criteria Decision Analysis (MCDA) can be used as a decision support tool to facilitate priority setting for environmental public health interventions within local authorities. We combine modelling and expert elicitation to gather evidence on the impacts and ranking of interventions. Methods To present the methodology, we consider a hypothetical scenario in a UK city. We use MCDA to evaluate and compare the impact of interventions to reduce the health burden associated with four environmental health hazards and rank them in terms of their overall performance across several criteria. For illustrative purposes, we focus on heavy goods vehicle controls to reduce outdoor air pollution, remediation to control levels of indoor radon, carbon monoxide and fitting alarms, and encouraging cycling to target the obesogenic environment. Regional data was included as model evidence to construct a ratings matrix for the city. Results When MCDA is performed with uniform weights, the intervention of heavy goods vehicle controls to reduce outdoor air pollution is ranked the highest. Cycling and the obesogenic environment is ranked second. Conclusions We argue that a MCDA based approach provides a framework to guide environmental public health decision makers. This is demonstrated through an online interactive MCDA tool. We conclude that MCDA is a transparent tool that can be used to compare the impact of alternative interventions on a set of pre-defined criteria. In our illustrative example, we ranked the best intervention across the equally weighted selected criteria out of the four alternatives. Further work is needed to test the tool with decision makers and stakeholders. Electronic supplementary material The online version of this article (doi:10.1186/s12940-016-0099-y) contains supplementary material, which is available to authorized users.

Where U i is an intervention uptake rate variable which takes a value between 0 and 1, where 1 is complete uptake by the effected population (N i ). This could then perhaps be left as a free parameter to model to derive required uptake rates for an intervention in order to make it the most acceptable one.
While the authors hint at the need for some sensitivity analysis in the discussion, without examining the impact of adjusting the weights and the interactions and varying Δe i (or U i ) it is difficult to feel confident about the observations. The text content is clear and concise [a few typos aside] and the tables and figures are easy to read, however it is difficult to find some elements e.g. morbidity component for Radon in the main text and the overall clarity would be enhanced by a table in the body of the main text indicating the values of the variables in Eq. 4 for each intervention for both morbidity and mortality.
The author's discussion and conclusions are generally sound. As discussed earlier It would have been helpful, to include discussion of the current extent of application/use of the MCDA, alternative approaches, and existing practice in the UK.
Also worthy of mention in the discussion is the fit of this work with more strategic approaches including the use of ecological linkage frameworks which more explicitly incorporate the 'distal' determinants of 'health' outcomes and related policy levers across the breadth of local settings.

INTRODUCTION
The article introduces the methodology of a planning and intervention tool to be promoted towards decision makers and stakeholders. It starts from the need of discipline and policies integration in the field of land planning and it aims at implementing a rational and transparent tool for decision makers.

GENERAL REMARKS
• The objective of the article is highly embraceable and innovative and it is probably urgent! It may be an helpful clue for the need to link scientific evidence and political decisions • As it is claimed in the article MCDA is aimed at providing clear criteria for decision makers (belonging to public and private sectors) to chose among different options. Hence it would be useful to provide some more comments and suggestions, at least in view of future development, on: o Costs-benefits analysis or similar approach which might be useful to be introduced in this field; o Economic approach which is surely disputable (eg in terms of ethics), but yearns for objectiveness and transparency; o Cost analysis which might be helpful for the private sector, such as insurances.
• Even though it is mentioned in the article, it should be emphasized that the future efforts will be focused in view to the compliance with this approach of decision makers. In other word it should be declared that this work is preliminary and the future endeavours will mainly focus on the friendliness of the product. In fact it will be used by laypersons, and first and foremost it must be easily understood by decision makers who must rely on this approach.

MAJOR REMARKS
1. It's necessary to specify with more details the quality criteria, in particular "robust evidence" and "level of regulation" (page 9). Please note that the definition of the qualitative criteria (reported in the section Results, page 15-16) must be deployed in the section Methods, after the explanation of quantitative criteria). Finally note that at page 20 (in the section Discussion), other 3 criteria are cited which have never been mentioned in section Methods. 2. It's recommended to discuss more deeply the part of environmental hazards and the related interventions as the reader should pay more attention to Table 1. 3. In the section relating to quantitative criteria (page 10), the excess relative risks are referred to all-cause mortality, whilst for some environmental risks presented in the section Results, these excess relative risks are referred to specific-cause mortality. Moreover, in morbidity's formula, the term d R is defined as incidence rate, whilst in the section Results it is always a prevalence rate.