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Reading Scientific Papers Shimae Soheilipour 1391-92.

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Presentation on theme: "Reading Scientific Papers Shimae Soheilipour 1391-92."— Presentation transcript:

1 Reading Scientific Papers Shimae Soheilipour 1391-92

2 Tell me Your Name Your experience of research if any Sh. Soheilipour

3 what you gain by reading the original scientific literature? Communicating the results and ideas to other scientists. Literature review to understand what has already been discovered and what questions remain unanswered: – Finding an idea for a research project – Doing original scientific research Sh. Soheilipour

4 Overview of Epidemiologic Study Designs

5 Why do research? To improve practice Personal development Sh. Soheilipour

6 Outline For This Section Focus on 5 study designs o Cross sectional o Case-control o Cohort o Randomized Control Trial o Review Narrative Systematic Meta Analysis

7 3 questions? 1.What was the research question? (Why was the study needed?) 2.What was the research design? 3.Was the research design appropriate to the question? Sh. Soheilipour

8 Type of research question Descriptive questions Knowledge Questions of relationships Association Questions of comparisons Intervention Sh. Soheilipour

9 PI(E)CO P : Patients, Population I or E: Intervention/Exposure C: Comparison O: Outcome Sh. Soheilipour

10 Type of research studies Experimental Studies Observational Studies Sh. Soheilipour

11 Study designs Primary Literature o Observational Cross sectional Case-Control Cohort o Experimental Randomized Control Trial Secondary Literature o Narrative Reviews o Systematic Review o Meta Analysis Joe Pozdol, MLIS

12 Three important points in designing an epidemiologic study Directionality Sample selection Timing Sh. Soheilipour

13 Experimental Studies (trial) Preventions and treatments for diseases; Investigator actively manipulates which groups receive the agent under study. – A preventive or prophylactic trial – A therapeutic or clinical trial Or – Controlled – Without controlled Joe Pozdol, MLIS

14 RCTs A treatment group is compared to a control group Group members are assigned randomly Best uses: – Drug therapies – Medical treatments Sh. Soheilipour

15 RCTs Recovery Not relief Time Present Intervention Future Placebo Patients Not relief Recovery Dr Farajzadegan

16 Observational Studies Causes, preventions, and treatments for diseases; Investigator passively observes as nature takes its course. – Cohort : Typically examines multiple health effects of an exposure; subjects are defined according to their exposure levels and followed for disease occurrence – Case–control: Typically examines multiple exposures in relation to a disease; subjects are defined as cases and controls, and exposure histories are compared. – Cross-sectional: Examines relationship between exposure and disease prevalence in a defined population at a single point in time. Sh. Soheilipour

17 Cohort Two groups compared over time One group with “exposure”, the other without the “exposure” Best used: o when exposures can’t be controlled o when outcomes occur infrequently o when RCT is not ethical Joe Pozdol, MLIS

18 Cohort Diseased Healthy Time Present Exposure Future Non exposure Samples Healthy Diseased Dr Farajzadegan

19 Cohort Diseased Healthy Time Present Exposure Future Non exposure Samples Healthy Diseased Past Dr Farajzadegan

20 Case-control Patients with a disease or exposure --compared to-- Similar group without disease or exposure Best uses o Rare conditions o Diseases or conditions that may take a long time to develop Joe Pozdol, MLIS

21 Case- control Exposure Diseased (Case) Healthy (Control) Time Present Non Exposure Exposure Past Dr Farajzadegan

22 Cross sectional Prevalence estimation Description Disease grading Diagnosis Joe Pozdol, MLIS

23 Cross sectional Samples Diseased Healthy Time Present Dr Farajzadegan

24 Narrative Reviews The “traditional” or “classic” review “Review” limit in Ovid/PubMed includes: – Narrative reviews – Systematic reviews Authors choose articles included Author bias is a concern – research verifies this effect Joe Pozdol, MLIS

25 Systematic Review Reproducible methods to find and select articles are included Should include both inclusion and exclusion criteria Why? Decrease author bias Joe Pozdol, MLIS

26 Meta Analysis Similar to Systematic Review except… Numeric data from separate studies combined in meta analysis Uses statistical/mathematical methods to combine numerical data from studies Combining data increases the confidence we have in the conclusions reached by a meta analysis Joe Pozdol, MLIS

27 The Evidence Pyramid Used for Evidence-Based Medicine Joe Pozdol, MLIS

28 How to read a scientific paper?

29 Types of Scientific Papers Review articles Primary research articles A few easy ways to distinguish 1- Many reviews will be labeled as "review" or "tutorial" on the first page of the article. 2- Reviews don't have a "methods" section 3- In a review article, graphs, tables, or figures containing actual data will contain citations in the figure legend to the primary research papers that originally reported the findings

30 The Parts of Primary Research Articles  Title and authors  Abstract  Introduction  Materials and Methods  Results  Discussion and Conclusion  Acknowledgements  References

31 Title Briefly states what the article is about

32 Abstract Summarizes Often only part read Don’t act on abstracts alone Structured abstracts are norm – Background – Methods – Results – Conclusions How does it help you? 1- Abstracts are usually accessible for free either online at journals' websites or in scientific literature databases. 2- Decide if the article was what you were looking for, or not. Joe Pozdol, MLIS

33 Introduction Context What is known Supporting literature (citations) Gaps in literature The research question Newness Relevance to field Joe Pozdol, MLIS

34 Materials and Methods Describes the research procedure and gives the technical details of how the experiments were carried out. Steps taken to – gather data – analyze data Statistical methods Replicable In reality, often compressed and you may need to look up another paper that is referenced for more detail.

35 Results Report of data Tables and graphs Statistical results No interpretation Joe Pozdol, MLIS

36 Results Results are often simply stated with interpretation of them coming later in the discussion. Figures and tables allow the reader to see the outcomes of the experiments for themselves!

37 Discussion Interpretation of results Answer to research question Goals met? Often includes – relation to previous research – limitations – future directions The purpose of discussion sections in papers is to allow the exchange of ideas between scientists. As such, it is critical to remember that the discussions are the authors' interpretations and not necessarily facts Joe Pozdol, MLIS

38 Conclusion Focuses the reader on what is important about the research, its contribution to the larger area of study.

39 References lists the sources used in the article Review articles Primary research articles, Books or other relevant sources Citation styles differ depending on – field of study (e.g. AMA vs. APA) – journal EndNote and RefWorks

40 By now, you may be tired of this paper… but don’t relax yet. Save energy for the overall reflection and criticism Kelly Hogan

41 Group work What was the aim of the study? What was the back ground of the study? What was the study design? What type of measurements were used and how they were made? How were measurements analysed? What was the drop-out rate? What were the stated findings? What were the stated conclusions? Were the conclusions justified? Discussed the study quality and contribution to the knowledge?

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