Scandinavian Journal of Public Health

This introductory paper considers the value and limitations of the methodology of systematic reviews especially according to the evidence-based movement. It explains some terms and organisations producing systematic reviews. It also discusses controversies. The first concerns the criteria by which the quality of individual studies is assessed, the second the possible effects of the affiliation of some reviewers, and the third the value of formalisation of procedure (i.e. the tensions between formal tools and professional judgments). The article contrasts the evidence-based formalism with other formalisms as those by the Intergovernmental Panel on Climate Change and the International Agency for Research on Cancer. It discusses systematic reviews in social science where interventions are complex, difficult to blind, and depend on context. Systematic reviews in working life research are often focusing on prevention. The formal evidence-based process may devaluate or disregard findings from mechanistic and observational studies. Hence such reviews may falsely conclude that existing knowledge about the risk of the factor is limited or nonexistent.

The evidence movement and the idea of systematically synthesising results from primary studies has gained support in recent years. As the movement has moved into still more policy fields, from medical treatment to, for example, public health, social welfare, and education, review practice has also been developed. The initial evidence hierarchy based standard given priority to randomised controlled trials and meta-analysis advocated by the Cochrane and Campbell collaborations has become supplemented with evidence typologies and review practice paradigms stressing the importance of contextual factors as explanations of differences in effects. In addition to analysing and discussing this development, the article discusses the organisation of dissemination of evidence. This topic is interesting because it is part of the self-perception of the evidence movement that evidence should be brought to use in both practice and policy making.

The use of evidence in practice and policy in public health and social services is a tricky endeavour. While virtually every practitioner, manager, or policy maker would agree that evidence should be used, there is disagreement about the nature of evidence and which evidence should be used, how, when, in what circumstances, and for whom. Within these disagreements, however, can be found some essential truths: (1) scientific knowledge evolves over time; (2) different types of evidence are needed for different purposes; (3) evidence has a range of quality; (4) synthesising multiple forms of evidence is difficult and inevitably includes some level of subjectivity; and (5) effective implementation of evidence is as important as the decision to use evidence in the first place. This paper will discuss the use of evidence in practice in what is arguably the most complex helping environment – social services – detailing the emergence and evolution of evidence-informed practice, dispelling some myths about its structure and application, and linking it to the broader origins and structure of the social and governmental systems in which it operates. Using this expanded view, the paper will then describe some useful approaches for incorporating these larger considerations into the use of evidence in practice.

In this paper I discuss how evidence on public policy is generated and in particular the issue of evaluation of public policies. In economics, the issue of attribution and the identification of causal links has recently received considerable attention. Important methodological issues have been tackled and new techniques have been proposed and used. Randomized Control Trials have become some sort of gold standard. However, they are not exempt from problems and have important limitations: in some case they cannot be constructed and, more generally, problems of external validity and transferability of results can be important. The paper then moves on to discuss the political economy of policy evaluations for policy evaluations to have an impact for the conduct of actual policy, it is important that the demand for evaluation comes directly from the policy making process and is generated endogenously within it. In this sense it is important that the institutional design of policy making is such that policy making institutions are incentivized to use rigorous evaluation in the process of designing policies and allocating resources to alternative options.

Economists are currently involved in the design and evaluation of many policies, including policies about health, nutrition and education. The role they can play in these fields is not completely obvious. The paper argues that their main contribution is in the modelling of how individual reacts to incentives (including those provided by public policies).

The epistemological basis of clinical trials and evidence-based medicine is investigated. Clinical trials are directly action-guiding experiments on treatment effects. This is the reason why well-performed clinical trials take precedence over all other types of studies as far as treatment effects are concerned. The efficiency of public health interventions can be studied with directly action-guiding experiments that have the same strong epistemic justification as clinical trials. However, in order to assess the causality of diseases, information from several types of studies will have to be combined. Here, no single type of studies has priority over all the others. Therefore, evidence hierarchies are less helpful in studies of causality than they are in investigations of the effects of treatments or interventions.

Musculoskeletal disorders (MSDs) affecting the back, upper and lower extremities are widespread in the general population, implying a variety of causal factors. Multiple causes are not mutually exclusive, and a high background rate does not preclude associations with specific factors that are uncommon in the general population. MSDs have well-documented associations with occupational ergonomic stressors such as repetitive motion, heavy lifting, non-neutral postures, and vibration. Organizational features of the work environment, such as time pressure and low decision latitude, may also play a role, at least by potentiating the effects of physical loading. Numerous systematic reviews have mostly concurred with these overall findings. Nevertheless, some continue to debate whether MSDs are sometimes work-related, even for those performing jobs with repetitive and routinized tasks, heavy lifting, and/or pronounced postural strain. This article discusses (1) some epidemiologic features of MSDs that underlie that debate; and (2) the question of what should appropriately be considered a gold standard for scientific evidence on an etiological question such as the health effects of a non-voluntary exposure, such as an occupational or environmental agent. In particular, randomized clinical trials have little relevance for determining the health effects of non-therapeutic risk factors.

Aims: Social practitioners require evidence-based knowledge as a guide to the development of social policies and practices. This article aims to identify: (1) knowledge domains needed for the development and use of evidence-based knowledge in social practice; (2) promising research methods for such knowledge development; (3) a framework for linking evidence-based practice, systematic reviews, and practice guidelines, as well as standards for systematic reviews and guidelines; (4) issues influencing use of evidence-based knowledge in social practice. Methods: This analysis is based on examination of conceptualisations of social practice in a transdisciplinary, evidence-based practice context. Also examined are recent national level reports pertaining to comparative effectiveness research. Results: This review identifies key knowledge domains pertinent to a transdisciplinary systems conceptualisation of evidence-based practice and promising comparative effectiveness research methods pertaining to those domains. An integrative conceptualisation of evidence-based practice is proposed including linkages to systematic reviews and practice guidelines. Conclusions: The development of evidence-based knowledge for social practice can benefit from the use of comparative effectiveness research strategies using a range of research methods tailored to specific questions and resource requirements, and which examine effectiveness and cost-effectiveness. An integrating conceptualisation of evidence-based practice that includes a linked process including planned and targeted systematic reviews and guideline development for decision making is needed to facilitate knowledge development and use. Evidence-based research regarding social intervention outcomes can benefit by using conceptual models that view intervention effects as contingent on sets of interacting domains including environmental, organisational, intervener, client-system, technology, and technique variables.