Traditional form of ‘literature review’ normally reports the findings part of other researches related to one’s own research questions, not necessarily it goes for appraising critically methods used in conducting these researches. There might be numerous number of research studies in a specific research area, not necessarily all were conducted following appropriate methodology. But more importantly, are all these findings reported valid, reliable and useful? Why is it important to be findings reliable? How can policy makers, professionals and practitioners identify sound research evidences for policy formulation and outlining strategies? Here it comes the idea of ‘systematic review’, started first back in 1975 in the field of healthcare, but later it has now been being used in other areas including education, social care, crime and justice, employment etc. A ‘systematic review’ is mainly a scientific, methodological, rigorous review of existing literature which actually examines the results of other researches whether the evidences are valid, reliable and useful. It is a kind of research aiming to answer a particular research question by looking at as much as possible relevant researches that also aimed at answering same type of research question. It then picks up only reliable evidences from those researches following a standard set of processes. The ‘systematic review’ uses explicit, rigorous and transparent methods in doing so. The very procedures of ‘systematic review’ make it accountable, replicable and updateable. It also makes sure the involvement of the users of that particular research outputs in order to make it very relevant and useful. Then finally, ‘systematic review’ synthesizes those varied and reliable evidences available for all who will need to use it. Traditionally ‘systematic review’ was employed to assess the researches having mainly experimental/interventional design but now the use of ‘systematic review’ for assessing researches of other designs has been increased.
The ‘systematic review’ has following six special features that make it very different from general ‘literature review’:
(i) ‘Systematic review’ considers all researches relevant to the particular research question of the review. They are evaluated then following a set of standards and their quality and relevance are made clear. Thus ‘systematic review’ is very transparent in the process of generating its conclusion.
(ii) ‘Systematic review’ sets out its working methodology at the very beginning. Thus it helps working methodology not to be influenced by the result of the reviews later and it reduces bias.
(iii) ‘Systematic review’ conducts extensive searches to find out almost all researches relevant to the particular research question of the review. Thus it reduces the bias of having only influenced by the most accessible researches.
(iv) ‘Systematic review’ reports its own methodology explicitly so that readers have all the information about them. And if anyone later wants to critically appraise that review s/he has all the related details there.
(v) ‘Systematic review’ normally involves representatives from all the user groups of that particular research in order to make it very relevant and useful.
(vi) ‘Systematic review’ only synthesizes the result of the sound researches that it identifies. And these varied and reliable evidences are made available for the uses of people who want to use it.
These above mentioned six distinguishing features also make ‘systematic review’ very important.
‘Systematic review’ adopts the methodology depending upon the research design demands by the nature of particular research question. There are already a good number of published quality appraisal tools which it adopts according to the type of study. In general, the ‘systematic review’ methodology considers the following areas to review all relevant researches. Firstly, it assesses the methodologies used in conducting a study whether it followed the established norms of that particular type of study or not. This is concerned to the quality aspect of the methodology. Secondly, it examines the appropriateness of the methodology used in a particular research in answering the research question of the review; this is related to the relevancy aspect of the methodology. Thirdly, it explores whether the research focuses rightly in answering the particular research question which is concerning to the topic relevancy. Finally, an overall rating of weight of evidence is given based upon the above mentioned three criteria. The total methods are used in assessing the researches and as a result, the evidences come out through this process are both trustworthy and relevant. This is considered as the strength of the ‘systematic review’. It is also mentioned that, depending on the particular nature of the research question, the review design may consider to include all the above mentioned three criteria or less.
The ‘systematic review’ is very important especially in the case of evidence based policy formulation and strategy outlining process. If the policies are not formulated upon sound evidences it might hinder the efficiency of policy formulation and strategy outlining system. And more from a micro level, an inappropriate policy formulation does have a lot of implications including financial, resources and time. Thus, it is growing more and more general consensus now everywhere that policies and strategies formulation must be based upon sound research evidences. To understand and identify only valid, reliable and useful evidences, ‘systematic review’ is a scientific, methodological and rigorous process. ‘Systematic review’ identifies only well designed and well conducted researches and examine them and then synthesizes their results which are varied, reliable and useful. Thus it provides evidences based knowledge for the users to use. Therefore, the ‘systematic review’ has been emerged as very important to the policy makers, professionals and practitioners who want to formulate their policies and outline strategies based upon sound evidences from the researches. In addition, it might be viable to put the argument, the idea of general ‘literature review’ may be considered to be replaced by the ‘systematic review’ in the near future among the entire researchers community. All the graduate research studies and other mainstream researches do conduct ‘literature review’ anyway. Then why not incorporating ‘systematic review’ in it? The reason for arguing this is comparing to the short time scale of evolving of ‘systematic review’ in the research world and now its wider acceptance among all the policy makers and practitioners. A general consensus about ‘systematic review’ among the researchers community might make the research effort more efficient and trustworthy.
Note: The article is written here followed the ‘systematic review’ content available on the website of ‘The Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre)’, part of the Social Science Research Unit at the Institute of Education, University of London. The EPPI-Centre website can be accessed through the link http://eppi.ioe.ac.uk/cms/Default.aspx?tabid=53
MIRON KUMAR BHOWMIK: PhD Researcher at the Hong Kong Institute of Education, Hong Kong, China.