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INTRODUCTION TO SCIENTIFIC PAPERS Joe Pozdol, MLIS Evans Whitaker, MD, MLIS Norris Medical Library University of Southern California 2003 Zonal Ave. Los.

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Presentation on theme: "INTRODUCTION TO SCIENTIFIC PAPERS Joe Pozdol, MLIS Evans Whitaker, MD, MLIS Norris Medical Library University of Southern California 2003 Zonal Ave. Los."— Presentation transcript:

1 INTRODUCTION TO SCIENTIFIC PAPERS Joe Pozdol, MLIS Evans Whitaker, MD, MLIS Norris Medical Library University of Southern California 2003 Zonal Ave. Los Angeles, CA

2 Before We Begin… Ask! PowerPoint at under Key Resources for Studentswww.usc.edu/nml Interactive questions Handouts Article later Evaluation Unwanted handouts

3 Outline For Today I. Parts of a paper A. Abstract B. Introduction/Background C. Methods D. Results E. Discussion F. References (Bibliography) II. Study types A. Primary 1. Observational 2. Experimental B. Secondary III. Group work IV. Evaluations

4 PART I SECTIONS OF A PUBLISHED SCIENTIFIC PAPER

5 Part I Objectives Learn the basic structure of papers Develop an approach to reading papers Learn how to interpret an article citation

6 The Basic Parts Title Abstract Introduction Methods Results Discussion References

7 Read In This Order Title Abstract Introduction/ Discussion Methods/ Results

8 The discussion section occurs before the author presents the results of the study. 1.True 2.False

9 Which occurs first in a scientific journal article? 1.Abstract 2.Discussion 3.Introduction 4.Methods 5.Results

10 Abstract Summarizes Often only part read Dont act on abstracts alone Structured abstracts are norm –Background –Methods –Results –Conclusions

11 Introduction Context What is known Supporting literature (citations) Gaps in literature The research question Newness Relevance to field

12 Methods Steps taken to –gather data –analyze data Statistical methods Not a cookbook Replicable

13 Results Report of data Tables and graphs Statistical results No interpretation

14 Discussion Interpretation of results Answer to research question Goals met? Often includes –relation to previous research –limitations –future directions

15 Which should allow other researchers to replicate the study? 1.Abstract 2.Discussion 3.Introduction 4.Methods 5.Results

16 Limitations of the study are found in the… 1.Abstract 2.Discussion 3.Introduction 4.Methods 5.Results

17 References List of sources cited in intro Usually other journal articles Previous studies in same field Citation styles differ depending on –field of study (e.g. AMA vs. APA) –journal EndNote and RefWorks

18 Understanding Journal Article References Weiss, PA. Does smoking marijuana contribute to the risk of developing lung cancer? Clinical Journal of Oncology Nursing. 2008;12(3): Journal Volume Number Issue Number Researchers Article

19 Which cannot be determined from a reference list citation? 1.Title of the journal 2.Title of the journal article 3.Number of pages in the journal 4.Number of pages in the journal article 5.None of the above

20 Whether marijuana use causes lung cancer is still unknown and will likely be a subject of research in the next 5 years. 1.True 2.False

21 PART II TYPES OF SCIENTIFIC PAPERS

22 Part II Objectives Learn the common study types Be able to extract the research question Be able to identify an articles study type Be able to determine the conclusions

23 Outline For This Section Focus on 4 study designs o Case-control o Cohort o Randomized Control Trial o Review Narrative Systematic Meta Analysis

24 3 questions to get your bearings3 questions to get your bearings * 1.What was the research question? 2.What was the research design? 3.Was the research design appropriate to the question? Will try to find answers to 1 and 2 in excerpts of 4 articles (A-D) provided * - Greenhalgh, T. (2006). How to read a paper: the basis of evidence-based medicine. Malden, MA: Blackwell

25 Study Designs Primary Literature o Observational Case-Control Cohort o Experimental Randomized Control Trial Secondary Literature o Narrative (Subject/Journalistic) Reviews o Systematic Review o Meta Analysis

26 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

27 Background: DES Used in the United States from 1947 until 1971 Boston area doctors noted an unusual cancer Study compared the group with the cancer to similar people without the cancer The major difference between the cases and the controls was DES exposure

28 Example: DES and Cancer Herbst, A.L., Ulfelder, H., & Poskanzer,D.C. (1971). Adenocarcinoma of the vagina: association of maternal stilbestrol therapy with tumor appearance in young women. NEJM, 284(16), Look at article: –Last sentence in Introductory area = research question –First paragraph in methods = research design

29 Why did the authors match cases and controls by the type of service mothers received?* * -see page To reduce socioeconomic differences 2.To examine whether the cancer was related to infectious disease exposures 3.To decide if chemical disinfectants used to clean wards caused cancer 4.All of the above

30 How many of the 8 cases mothers were given estrogen in pregnancy (DES)? 1.All 2.Seven 3.Five 4.Three 5.One 6.None 30

31 Cohort Two groups compared over time One group with exposure, the other without the exposure Best used: o when exposures cant be controlled o when outcomes occur infrequently o when RCT is not ethical

32 Example: Smoking vs. Non-Smoking British Physicians Doll, R., Peto, R., Boreham, J., & Sutherland, I. (2004). Mortality in Relation to Smoking: 50 years' observations on male British doctors. BMJ, doi: /bmj AE 50 years (and counting) Cohort Study of British doctors Most recent of a series of reports Compared health outcomes of smokers vs. health outcomes of non-smokers Research question = Research design =

33 When was there enough evidence from this study to show the link between smoking and lung cancer?

34 Randomized Control Trial A treatment group is compared to a control group Group members are assigned randomly Best uses: –Drug therapies –Medical treatments

35 Example: Smoking cessation intervention An, L.C., Klatt, C., Perry, C.L., Lein, E.B., Hennrikus, D.J., et al. (2008). The RealU online cessation intervention for college smokers: a randomized control trial. Preventive Medicine, 47(2) Look at the article: o The last paragraph of the introduction - research question o The last paragraph of the introduction - research design o Study flow chart - pg. 196

36 25,000 UM students were recruited by How many UM students ended up in the intervention group? 1. 24, ,

37 What percent of RealU participants had 30 days of no smoking at week 30? 1.100% 2.80% 3.60% 4.40% 5.20% 6.none 30

38 Narrative (Journalistic/Subject) 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

39 Systematic Review Reproducible methods to find and select articles are included Should include both inclusion and exclusion criteria Why? Decrease author bias

40 Example: Is HPV Vaccine Cost-Effective? Techakehakij, W., Feldman, R.D. (2008). Cost- effectiveness of HPV vaccination compared to Pap smear screening on a national scale: a literature review. Vaccine, doi: /j.vaccine Look at article: –Pg. 2, Section 3.1, first paragraph = research question –Pg. 3, Section 4.1, first to third paragraphs = research design

41 It is recommended that HPV vaccine be given as a 3 shot series. How much do 3 doses of vaccine cost? 1.$500-$ $300-$500 3.$200-$300 4.$100-$200 30

42 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

43 GROUP WORK

44 Group Work Groups of 3 Everyone in group gets same article (#1, 2, 3, OR 4) Spend 10 min. working together on questions Class discussion

45 ADDITIONAL SLIDES

46 Article Type What kind of question is it good for? StrengthsWeaknesses Identifying Characteristics Case-Control (Herbst, 1971) (Peled, 2008) -Rare disorders or conditions -Slow developing disorders -Causation* -Short time frame to examine correlations between disorder and other factors -Susceptible to bias -Limited validity -Cross sectional Cohort** (Doll, et al, 2004) (Metcalf, 2008) - Prognosis -Causation* - Feasible when studying conditions or exposures over which the investigator has no control -Susceptible to bias -Limited validity -May require large groups, long durations, great cost -Longitudinal -Usually prospective -Can be retrospective (less cost) Randomized Control Trial (RCT) (An et al, 2008) (Gordon, 1997) -Drug treatment -Medical interventions -Strong level of evidence -Low susceptibility to bias -Feasibility (e.g. Ethical limitations) -Generalizability** -Randomization method - Experimental and control groups Systematic Review (Techakehakij,2008) (Gallicchio, 2008) -Drug treatment -Medical interventions -Low susceptibility to bias -Strongest level of evidence -Many topics have no systematic review -Methods section has explicit information about information sources, how articles were chosen or excluded * - used loosely here; not distinguishing between correlation and causation (in medicine etiology is used for the cause of a disease or condition) ** - can results of an RCT be applied to groups that do not match the study group?

47 The Evidence Pyramid Used for Evidence-Based Medicine

48 Thanks for your attention We will post these slides on the Student Portal on the Norris Medical Library website Student Portal Contact us with questions –Joe Pozdol – –Evans Whitaker – Please complete evaluations!

49 References An, L.C., Klatt, C., Perry, C.L., Lein, E.B., Hennrikus, D.J., et al. (2008). The RealU online cessation intervention for college smokers: a randomized control trial. Preventive Medicine, 47(2) Doll, R., Peto, R., Boreham, J., & Sutherland, I. (2004). Mortality in Relation to Smoking: 50 years' observations on male British doctors. BMJ, doi: /bmj AE Gallicchio, L., Boyd, K., Matanoski, G., et al. (2008). Carotenoids and the risk of developing lung cancer: A systematic review. Am.J.Clin. Nutrit., 88, Gordon, C.M., Carey, M.P., & Carey, K.B. (1997). Effects of a drinking event on behavioral skills and condom attitudes in men: Implications for HIV risk from a controlled experiment. Health Psychology, 16(5), Greenhalgh, T. (2006). How to read a paper: the basis of evidence- based medicine. Malden, MA: Blackwell. Guyatt, G., Rennie, D. (eds.). (2001). Users guides to the medical literature: essentials of evidence-based clinical practice. Chicago: AMA Press.

50 References Herbst, A.L., Ulfelder, H., & Poskanzer,D.C. (1971). Adenocarcinoma of the vagina: association of maternal stilbestrol therapy with tumor appearance in young women. NEJM, 284(16), Metcalf, B.S., Voss, L.D., Hosking, J., & Wilkin, J.T. (2008). Physical activity at the government-recommended level and obesity- relatedhealth outcomes: a longitudinal study (Early Bird 37). Archives of Diseases of Childhood (Early Bird 37). 93, Peled, R. Carmil, D., Siboni-Samocha, O., & Shoham-Vardi, I. (2008). Breast cancer, psychological distress and life events among young women. BMC Cancer, 8,


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