The findings of this review have highlighted the substantial quantity of research which has focused on the validity, reliability and responsiveness to change of measures of PA. A substantial number of review articles have been conducted on the measurement of PA in adult populations. Of the systematic reviews articles identified, the methodological quality was relatively poor, with 3 reviews considered low quality, 16 articles considered medium quality and 3 articles considered high quality. An obvious increase in the quantity of research using objective measures of PA over the past number of decades is apparent. Unfortunately, with the enormous quantity of research on the methodological effectiveness of PA measures comes extreme variability in study design, data processing and statistical analysis conducted. Such variability makes comparison between measurement type and specific measurement devices/tools extremely difficult.
The sometimes questionable study designs and research questions in some of the existing published literature is a reanalysis of "suitable" data, rather than from a study designed to collect data to answer a specific research questions. The authors also propose that any future undertaking of reviews on the measurement of PA follow best practise, and ensure that the reviews conducted are of the highest possible quality. Such improvements will provide researchers with the best available evidence for making a decision on which measure of PA to employ. This review of reviews had limitations that should be taken into account when considering the findings presented here. As this article reviewed existing literature reviews, and due to potential methodological errors within these reviews, it is likely that some relevant literature on the methodological effectiveness for measures of PA has been overlooked. Additionally, articles that have been published since the publication of each review will also have been overlooked.
Due to the quantity of identified articles, and difficulties in contacting primary authors regarding articles published over the last 60 years, the primary data from these articles was not sourced. For researchers that are selecting a measure of PA, this will enable the comparison between different measures of PA within one article, rather than having to refer to a wide range of available literature that examines each single measure. Additionally, rather than focusing solely on information presented within each existing review of the literature, the original articles referred to within each review were sought and data was extracted independently. When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices (Paré et al., 2015). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies (Cooper, 1988; Rowe, 2014).
The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources (Cronin et al., 2008). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one's academic community (Paré et al., 2015; Petticrew & Roberts, 2006). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type. The criterion validity of measures was determined through the examination of energy expenditure via DLW and by direct observation of steps and PA behaviours.
For accelerometry, although variability was lower, a substantial proportion of studies (44/54) underestimated energy expenditure compared to DLW when proprietary algorithms or count-to-activity thresholds were employed. Based on the amended forest plots for the criterion validity of measures of PA, a greater level of variability was apparent for self-reported measures compared to objective measures (Figs. 2–6). Limited data on the criterion validity of HRM and combined sensors determined energy expenditure was available. HRMs tended to underestimate DLW determined energy expenditure, while combined sensors often overestimated energy expenditure. Unfortunately, due to the lack of measures of variability, resulting in the absence of meta-analysis, it was not possible to describe the extent of differences between measures statistically.
For step counts, both activity monitors and pedometers achieved high levels of criterion validity. When comparing the two, pedometers appeared to be less accurate than activity monitors at estimating step count, tending to underestimate steps when compared to direct observation. Activity monitors tended to slightly overestimate distance travelled, while time spent in each activity type determined by both activity monitors and combined sensors was slightly underestimated when compared to direct observation (Fig. 3a and Fig. 6). For concurrent validity of all measure of PA, high levels of variability were observed across a wide range of activity behaviours. In particular, high levels of variability were apparent in the estimation of PA intensities, with VPA substantially overestimated in the majority of concurrent validations across all measures.
In summary, objective measures are less variable than recall based measures across all behaviours, but high levels of variability across behaviours are still apparent. We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another (Paré et al., 2015). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review.
Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches (vom Brocke et al., 2009). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used.
We refer those interested in the concepts of rigour and quality to the work of Templier and Paré which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles. In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies (Petersen, Vakkalanka, & Kuzniarz, 2015). Indeed, structured search methods are used to form a representative sample of a larger group of published works (Paré et al., 2015). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain (King & He, 2005). Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research (Cronin et al., 2008).
Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature (Green et al., 2006). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues (Green et al., 2006). A peer reviewed journal article is a paper that has been submitted to a scholarly journal, accepted, and published.
Peer review journal papers go through a rigorous, blind review process of peer review. What this means is that two to three experts in the area of research featured in the paper have reviewed and accepted the paper for publication. The names of the author who are seeking to publish the research have been removed , so as to minimize any bias towards the authors of the research (albeit, sometimes a savvy reviewer can discern who has done the research based upon previous publications, etc.).
This blind review process can be long and may involve many back and forth edits on the behalf of the researchers, as they work to address the edits and concerns of the peers who reviewed their paper. Often, reviewers will reject the paper for a variety of reasons, such as unclear or questionable methods, lack of contribution to the field, etc. Because peer reviewed journal articles have gone through a rigorous process of review, they are considered to be the premier source for research. Peer reviewed journal articles should serve as the foundation for your literature review. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.
As shown in Table 9.1, each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles (Green et al., 2006). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions.
On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an "a priori" review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals. A literature review is an overview of the previously published works on a specific topic. The term can refer to a full scholarly paper or a section of a scholarly work such as a book, or an article. Either way, a literature review is supposed to provide the researcher/author and the audiences with a general image of the existing knowledge on the topic under question.
A good literature review can ensure that a proper research question has been asked and a proper theoretical framework and/or research methodology have been chosen. To be precise, a literature review serves to situate the current study within the body of the relevant literature and to provide context for the reader. In such case, the review usually precedes the methodology and results sections of the work.
The purpose of this article is to review existing reviews that have examined the methodological effectiveness of measures of PA. This review of reviews is intended to provide a concise summary of PA measurement in adults. This work was completed as a component of the European DEDIPAC collaboration.
Narrative or Traditional literature reviews critique and summarise a body of literature about the thesis topic. The literature is researched from the relevant databases and is generally very selective in the material used. The criteria for literature selection for a narrative review is not always made open to the reader.
These reviews are very useful in gathering and synthesising the literature located. Where a narrative approach differs from a systematic approach is in the notation of search methods criteria for selection,this can leave narrative reviews open to suggestions of bias. Although the validity, reliability and responsiveness to change are key when selecting a measure of PA and energy expenditure, other factors including feasibility and cost should be considered. The appropriateness of the measure for use in specific populations is critical.
Activity monitors or HRMs may need to be attached to body locations that are visible and may be considered "embarrassing" for certain populations in free-living environments, likely resulting in lower compliance to wear protocols. The links between increased participation in Physical Activity and improvements in health are well established. As this body of evidence has grown, so too has the search for measures of PA with high levels of methodological effectiveness (i.e. validity, reliability and responsiveness to change). The aim of this "review of reviews" was to provide a comprehensive overview of the methodological effectiveness of currently employed measures of PA, to aid researchers in their selection of an appropriate tool. A total of 63 review articles were included in this review, and the original articles cited by these reviews were included in order to extract detailed information on methodological effectiveness.
In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin as mapping reviews. Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped. However, there are three common mistakes that researchers make when including literature reviews in the discussion section.
First, they mention all sorts of studies, some of which are not even relevant to the topic under investigation. Second, instead of citing the original article, they cite a related article that mentions the original article. Lastly, some authors cite previous work solely based on the abstract, without even going through the entire paper.
To the authors' knowledge, this is the first systematic literature review of reviews to simultaneously examine the methodological effectiveness of the majority of PA measures. The greatest quantity of information was available for self-reported measures of PA , followed by activity monitors , pedometers , HRMs and combined sensors . Some reviews looked exclusively at specific PA behaviours (e.g. walking) or focused solely on validity and/or reliability issues . Other reviews have concentrated on methods for assessing PA in population subgroups (e.g. individuals with obesity or older adults) . Self-report measures of PA have been most frequently examined for methodological effectiveness, with highly variable findings identified across a broad range of behaviours.
The evidence-base for the methodological effectiveness of objective monitors, particularly accelerometers/activity monitors, is increasing, with lower levels of variability observed for validity and reliability when compared to subjective measures. Unfortunately, responsiveness to change across all measures and behaviours remains under-researched, with limited information available. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies ("sleeping beauties" )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile.
Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society. In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence . Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence.
Umbrella reviews, also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses (Becker & Oxman, 2008). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study (Becker & Oxman, 2008).
Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions (Smith, Devane, Begley, & Clarke, 2011). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.
Literature Review Meaning In English The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn't work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it.
You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources. When examining PA in free-living environments, it is essential that sufficient data is gathered to ensure a reliable estimate is obtained . By determining the inter- and intra-individual variability across days of measurement, researchers can define the number of days of monitoring required to reliably estimate such behaviours. For activity monitors and pedometers, analysis has been conducted to estimate the minimum number of days of measurement required to provide a reliable estimate of PA behaviors.
For pedometers, a minimum of 2-4 days of measurement was required to provide a reliable estimate of steps in older adults, while 2-5 days of measurement was required in adults. Their need stems from the ever-increasing output of scientific publications . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests .
Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read . For such summaries to be useful, however, they need to be compiled in a professional way . Kitsiou, Paré, and Jaana provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes.
