Select a Research Article Use the review article to select a research article. This can be very useful in writing your critique. Analyse the Text Read the article s carefully. As you read the article s use the following questions to help you understand how and why the research was carried out. What is the author's central purpose? What methods were used to accomplish this purpose systematic recording of observations, analysis and evaluation of published research, assessment of theory?
What were the techniques used? What kind of data can be obtained using each technique? How are such data interpreted? What kind of information is produced by using the technique?
What were the results of the study? How was each technique used to obtain each result? How did each result contribute to answering the question or testing the hypothesis raised in the introduction? How were the results interpreted? Were the author s able to answer the question test the hypothesis raised?
Source of questions in each section Wood, 4. Establish the Research Context Once you are reasonably familiar with the article, it is important to gain an understanding of the research context, both societal and intellectual.
To establish the research context, questions such as the following should be addressed: Who conducted the research? When and where was the research conducted? Why did they do this research? Was this research pertinent only within the authors' geographic locale, or did it have broader even global relevance?
Were many other laboratories pursuing related research when the reported work was done? If so, why? For experimental research, what funding sources met the costs of the research?
On what prior observations was the research based? What was and was not known at the time? How important was the research question posed by the researcher? For more detailed information on how to answer these questions, see Labs 4 and 5 Wood, Evaluate the Text After you have read the article and answered the questions in the previous section, you should have a good understanding of the research undertaken.
You can now begin to evaluate the author's research. Many students feel that, because they are new to a discipline, they do not have enough knowledge to make judgements of other people's work. What was the objective of the study? Keywords: publication, critical appraisal, decision making, quality assurance, study Despite the increasing number of scientific publications, many physicians find themselves with less and less time to read what others have written.
This is also demanded by the precepts of evidence-based medicine 1 , 2. Besides the medical content of a publication, its interpretation and evaluation also require understanding of the statistical methodology.
Sadly, not even in science are all terms always used correctly. The word "significance," for example, has been overused because significant or positive results are easier to get published 3 , 4. The aim of this article is to present the essential principles of the evaluation of scientific publications.
With the exception of a few specific features, these principles apply equally to experimental, clinical, and epidemiological studies. References to more detailed literature are provided. The references in review articles point the reader towards more detailed information on the topic concerned.
In the absence of any recent reviews on the desired theme, databases such as PubMed have to be consulted. Regular perusal of specialist journals is an obvious way of keeping up to date. The article title and abstract help the reader to decide whether the article merits closer attention. The abstract has the same basic structure as the article and renders the essential points of the publication in greatly shortened form.
Reading the abstract is no substitute for critically reading the whole article, but shows whether the authors have succeeded in summarizing aims, methods, results, and conclusions.
The structure of scientific publications The structure of scientific articles is essentially always the same. The title, summary and key words are followed by the main text. The content and purpose of the individual sections are described in detail below. Introduction The Introduction sets out to familiarize the reader with the subject matter of the investigation. The current state of knowledge should be presented with reference to the recent literature and the necessity of the study should be clearly laid out.
The findings of the studies cited should be given in detail, quoting numerical results. Inexact phrases such as "inconsistent findings," "somewhat better" and so on are to be avoided.
Overall, the text should give the impression that the author has read the articles cited. A good publication backs up its central statements with references to the literature. Ideally, this section should progress from the general to the specific. The introduction explains clearly what question the study is intended to answer and why the chosen design is appropriate for this end.
Methods This important section bears a certain resemblance to a cookbook. The description of the procedures should give the reader "recipes" that can be followed to repeat the study. The methods section can be divided into subsections with their own headings; for example, laboratory techniques can be described separately from statistical methods.
The methods section should describe all stages of planning, the composition of the study sample e. Was the investigation preceded by a pilot study? Are location and study period specified? It should be stated in this section that the study was carried out with the approval of the appropriate ethics committee. The most important element of a scientific investigation is the study design.
If for some reason the design is unacceptable, then so is the article, regardless of how the data were analyzed 7. The choice of study design should be explained and depicted in clear terms. If important aspects of the methodology are left undescribed, the reader is advised to be wary. If, for example, the method of randomization is not specified, as is often the case 8 , one ought not to assume that randomization took place at all 7. The statistical methods should be lucidly portrayed and complex statistical parameters and procedures described clearly, with references to the specialist literature.
Box 1 contains further questions that may be helpful in evaluation of the Methods section. Box 1 Is the study design suited to fulfill the aims of the study?
Is it stated whether the study is confirmatory, exploratory or descriptive in nature? What type of study was chosen, and does it permit the aims of the study to be addressed?
What statistical measure is employed to characterize the endpoint? Do epidemiological studies, for instance, give the incidence rate of new cases , prevalence current number of cases , mortality proportion of the population that dies of the disease concerned , lethality proportion of those with the disease who die of it or the hospital admission rate proportion of the population admitted to hospital because of the disease?
Are the geographical area, the population, the study period including duration of follow-up , and the intervals between investigations described in detail? Study design and implementation are described by Altman 7 , Trampisch and Windeler 9 , and Klug et al.
In experimental studies, precise depiction of the design and execution is vital. The accuracy of a method, i. The explanatory power of the results of a clinical study is improved by the inclusion of a control group active, historical, or placebo controls and by the randomized assignment of patients to the different arms of the study.
The quality can also be raised by blinding of the investigators, which guarantees identical treatment and observation of all study participants. A clinical study should as a rule include an estimation of the required number of patients case number planning before the beginning of the study. Do not assume that because your reader knows what you are writing about, you do not need to mention the work's title.
Other questions to consider: Is there a controversy surrounding either the passage or the subject which it concerns? What about the subject matter is of current interest? What is the overall value of the passage? What are its strengths and weaknesses? Support your thesis with detailed evidence from the text examined. Do not forget to document quotes and paraphrases. Remember that the purpose of a critical analysis is not merely to inform, but also to evaluate the worth, utility, excellence, distinction, truth, validity, beauty, or goodness of something.
Select a review article on a topic that interests you and that is written clearly so you can understand it. Regular perusal of specialist journals is an obvious way of keeping up to date. What kind of data can be obtained using each technique? The selection criteria and the rates of loss to follow-up permit conclusions as to whether the study sample is representative of the target population. Is it stated whether the study is confirmatory, exploratory or descriptive in nature? This is necessary to keep medical knowledge up to date and to ensure optimal patient care.
A clinical study should as a rule include an estimation of the required number of patients case number planning before the beginning of the study. How was each technique used to obtain each result? What methods were used to accomplish this purpose systematic recording of observations, analysis and evaluation of published research, assessment of theory? The Discussion must draw attention to any such differences and describe the patients who do not complete the study. A good study description includes information on missing values. The content and purpose of the individual sections are described in detail below.
Select a Research Article Use the review article to select a research article. Acknowledgements and conflict of interest statement This important section must provide information on any sponsors of the study. Consider the title. It is wrong to refer to an exploratory data analysis as a proof.
Wood, J. The reader does not require extensive methodological knowledge. Study design and implementation are described by Altman 7 , Trampisch and Windeler 9 , and Klug et al. Is the study innovative? Did practical difficulties e.
What is the author's central purpose? Discussion of appeal to a particular audience Remember: Avoid introducing your ideas by stating "I think" or "in my opinion. The second part, "Writing your Critique," discusses two possible ways to structure your critique paper.
This occurs when two closely connected risk factors are both associated with the dependent variable. Conclusion In this section, sum up the strengths and weaknesses of the research as a whole. Are the data organized for ready comparison and interpretation? Does all the information lead coherently to the purpose of the study?
Wood, J. Basic knowledge of study design, structuring of an article, the role of different sections, of statistical presentations as well as sources of error and limitation are presented. Does the study raise new, hitherto unanswered questions? What are the social, political, technological, medical implications of this research? For instance, the fact that smokers drink more coffee than average could lead to the erroneous assumption that drinking coffee causes lung cancer.