David Evans

Bio: David Evans is an academic researcher from University of South Australia. The author has contributed to research in topics: Health care & Systematic review. The author has an hindex of 31, co-authored 80 publications receiving 4712 citations. Previous affiliations of David Evans include Ohio State University & University of Adelaide.

Hierarchy of evidence: a framework for ranking evidence evaluating healthcare interventions

Abstract: A number of hierarchies of evidence have been developed to enable different research methods to be ranked according to the validity of their findings. However, most have focused on evaluation of the effectiveness of interventions. When the evaluation of healthcare addresses its appropriateness or feasibility, then existing hierarchies are inadequate. This paper reports the development of a hierarchy for ranking of evidence evaluating healthcare interventions. The aims of this hierarchy are twofold. Firstly, it is to provide a means by which the evidence from a range of methodologically different types of research can be graded. Secondly, it is to provide a logical framework that can be used during the development of systematic review protocols to help determine the study designs which can contribute valid evidence when the evaluation extends beyond effectiveness. The proposed hierarchy was developed based on a review of literature, investigation of existing hierarchies and examination of the strengths and limitations of different research methods. The proposed hierarchy of evidence focuses on three dimensions of the evaluation: effectiveness, appropriateness and feasibility. Research that can contribute valid evidence to each is suggested. To address the varying strengths of different research designs, four levels of evidence are proposed: excellent, good, fair and poor. The strength of the proposed hierarchy is that it acknowledges the valid contribution of evidence generated by a range of different types of research. However, hierarchies only provide a guide to the strength of the available evidence and other issues such as the quality of research also have an important influence.

An approach to the probability distribution of cusum run length

Abstract: The classical method of studying a cumulative sum control scheme of the decision interval type has been to regard the scheme as a sequence of sequential tests, to determine the average sample number for these component tests and hence to study the average run length for the scheme. A different approach in which the operation of the scheme is regarded as forming a Markov chain is set out. The transition probability matrix for this chain is obtained and then the properties of this matrix used to determine not only the average run lengths for the scheme, but also moments and percentage points of the run-length distribution and exact probabilities of run length. The method may be used with any discrete distribution and also, as ani accurate approximation, with any continuous distribution for the random variable which is to be controlled. Examples are given for the cases of a Poisson random variable and a normal random variable.

The effectiveness of music as an intervention for hospital patients: a systematic review

Abstract: The effectiveness of music as an intervention for hospital patients: a systematic review Introduction. Over the past few decades there has been a growing interest in the use of music, which has seen it used to achieve a diverse range of outcomes. While music as an intervention for hospital patients has subject to considerable evaluation, many of these studies are small and findings are therefore often contradictory. This systematic review was conducted to investigate the effectiveness of music as an intervention for hospital patients. Method. A comprehensive search was undertaken involving all major health care databases. For studies to be included in the review they must have investigated the effect of music, involved adult hospital patients and used a randomized controlled trial design. These studies must also have used outcome measures such as anxiety, satisfaction, pain, mood and vital signs. Identified studies were critically appraised, and then categorized according to whether music was evaluated during normal care delivery or during invasive and unpleasant procedures. When appropriate, studies were combined in a meta-analysis. Results. A total of 29 studies were identified that fulfilled the inclusion criteria, of which 10 were subsequently excluded following critical appraisal. Music played via headphones reduces anxiety of patients during normal care deliver, but it has no impact on the anxiety of patients undergoing procedures such as bronchoscopy, sigmoidoscopy or surgery with a spinal anaesthetic. Music produces a small reduction in respiratory rate during normal care delivery, but appears to have little effect on other vital sign parameters. It has no impact on the vital signs of patients undergoing procedures. Although the evidence is limited, music also appears improve the mood and tolerance of patients. Conclusion. This review demonstrates the effectiveness of music for the reduction of anxiety during normal care deliver. Given the inexpensive nature of this intervention, and the lack of adverse events, it is recommended as an adjunct to normal care practices. This review also highlights the need for further research into many aspect of this intervention.

Patient injury and physical restraint devices: a systematic review

Abstract: Objective. To investigate physical restraint-related injuries. Areas of interest were the prevalence of injury, types of injuries, risk of sustaining an injury and specific restraint devices associated with injury. Definitions. Injury in the context of this review was considered to be either direct injury, such as lacerations and strangulation, or indirect injury considered to be an adverse outcome such as increased mortality rates or duration of hospitalization. Method. A comprehensive search was undertaken that involved all major databases and the reference list of all relevant papers. To be included in the review studies had to involve people in acute or residential care settings and report data related to injury caused by restraint devices. A number of different types of research designs were included in the review. The findings of studies were pooled using odds ratio and narrative discussion. Results. The search identified 11 papers reporting the findings of 12 observational studies. These studies were supplemented with the findings of a number of other types of studies that reported restraint-related data. The review highlights the potential danger of using physical restraint in acute and residential health care facilities. Observational studies suggest that physical restraint may increase the risk of death, falls, serious injury and increased duration of hospitalization. However, there is little information to enable the magnitude of the problem to be determined. Discussion. Many of the findings highlight the urgent need for further investigation into the use of physical restraint in health care facilities. Further research should investigate the magnitude of the problem and specific restraint devices associated with injury. However, given the limited nature of the evidence, this association should be investigated further using rigorous research methods.

Database searches for qualitative research.

Abstract: Interest in the role of qualitative research in evidence-based health care is growing. However, the methods currently used to identify quantitative research do not translate easily to qualitative research. This paper highlights some of the difficulties during searches of electronic databases for qualitative research. These difficulties relate to the descriptive nature of the titles used in some qualitative studies, the variable information provided in abstracts, and the differences in the indexing of these studies across databases.

Cochrane Handbook for Systematic Reviews of Interventions

Abstract: The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.

Towards a Methodology for Developing Evidence-Informed Management Knowledge by Means of Systematic Review

Abstract: Undertaking a review of the literature is an important part of any research project. The researcher both maps and assesses the relevant intellectual territory in order to specify a research question which will further develop the knowledge base. However, traditional 'narrative' reviews frequently lack thoroughness, and in many cases are not undertaken as genuine pieces of investigatory science. Consequently they can lack a means for making sense of what the collection of studies is saying. These reviews can be biased by the researcher and often lack rigour. Furthermore, the use of reviews of the available evidence to provide insights and guidance for intervention into operational needs of practitioners and policymakers has largely been of secondary importance. For practitioners, making sense of a mass of often-contradictory evidence has become progressively harder. The quality of evidence underpinning decision-making and action has been questioned, for inadequate or incomplete evidence seriously impedes policy formulation and implementation. In exploring ways in which evidence-informed management reviews might be achieved, the authors evaluate the process of systematic review used in the medical sciences. Over the last fifteen years, medical science has attempted to improve the review process by synthesizing research in a systematic, transparent, and reproducible manner with the twin aims of enhancing the knowledge base and informing policymaking and practice. This paper evaluates the extent to which the process of systematic review can be applied to the management field in order to produce a reliable knowledge stock and enhanced practice by developing context-sensitive research. The paper highlights the challenges in developing an appropriate methodology.

Towards a Methodology for Developing Evidence-Informed Management Knowledge by Means of Systematic Review

Abstract: Undertaking a review of the literature is an important part of any research project. The researcher both maps and assesses the relevant intellectual territory in order to specify a research question which will further develop the knowledge hase. However, traditional 'narrative' reviews frequently lack thoroughness, and in many cases are not undertaken as genuine pieces of investigatory science. Consequently they can lack a means for making sense of what the collection of studies is saying. These reviews can he hiased by the researcher and often lack rigour. Furthermore, the use of reviews of the available evidence to provide insights and guidance for intervention into operational needs of practitioners and policymakers has largely been of secondary importance. For practitioners, making sense of a mass of often-contrad ictory evidence has hecome progressively harder. The quality of evidence underpinning decision-making and action has heen questioned, for inadequate or incomplete evidence seriously impedes policy formulation and implementation. In exploring ways in which evidence-informed management reviews might be achieved, the authors evaluate the process of systematic review used in the medical sciences. Over the last fifteen years, medical science has attempted to improve the review process hy synthesizing research in a systematic, transparent, and reproducihie manner with the twin aims of enhancing the knowledge hase and informing policymaking and practice. This paper evaluates the extent to which the process of systematic review can be applied to the management field in order to produce a reliable knowledge stock and enhanced practice by developing context-sensitive research. The paper highlights the challenges in developing an appropriate methodology.

The integrative review: updated methodology

Abstract: Aim. The aim of this paper is to distinguish the integrative review method from other review methods and to propose methodological strategies specific to the integrative review method to enhance the rigour of the process. Background. Recent evidence-based practice initiatives have increased the need for and the production of all types of reviews of the literature (integrative reviews, systematic reviews, meta-analyses, and qualitative reviews). The integrative review method is the only approach that allows for the combination of diverse methodologies (for example, experimental and non-experimental research), and has the potential to play a greater role in evidence-based practice for nursing. With respect to the integrative review method, strategies to enhance data collection and extraction have been developed; however, methods of analysis, synthesis, and conclusion drawing remain poorly formulated. Discussion. A modified framework for research reviews is presented to address issues specific to the integrative review method. Issues related to specifying the review purpose, searching the literature, evaluating data from primary sources, analysing data, and presenting the results are discussed. Data analysis methods of qualitative research are proposed as strategies that enhance the rigour of combining diverse methodologies as well as empirical and theoretical sources in an integrative review. Conclusion. An updated integrative review method has the potential to allow for diverse primary research methods to become a greater part of evidence-based practice initiatives.

Detection of abrupt changes: theory and application

Abstract: This book is downloadable from http://www.irisa.fr/sisthem/kniga/. Many monitoring problems can be stated as the problem of detecting a change in the parameters of a static or dynamic stochastic system. The main goal of this book is to describe a unified framework for the design and the performance analysis of the algorithms for solving these change detection problems. Also the book contains the key mathematical background necessary for this purpose. Finally links with the analytical redundancy approach to fault detection in linear systems are established. We call abrupt change any change in the parameters of the system that occurs either instantaneously or at least very fast with respect to the sampling period of the measurements. Abrupt changes by no means refer to changes with large magnitude; on the contrary, in most applications the main problem is to detect small changes. Moreover, in some applications, the early warning of small - and not necessarily fast - changes is of crucial interest in order to avoid the economic or even catastrophic consequences that can result from an accumulation of such small changes. For example, small faults arising in the sensors of a navigation system can result, through the underlying integration, in serious errors in the estimated position of the plane. Another example is the early warning of small deviations from the normal operating conditions of an industrial process. The early detection of slight changes in the state of the process allows to plan in a more adequate manner the periods during which the process should be inspected and possibly repaired, and thus to reduce the exploitation costs.