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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 Angeles, CA 90089-9130 pozdol@usc.edu ewhitake@usc.edu. Before We Begin…. Ask!
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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 Angeles, CA 90089-9130 pozdol@usc.edu ewhitake@usc.edu
Before We Begin… • Ask! • PowerPoint at www.usc.edu/nml under Key Resources for Students • Interactive questions • Handouts • Article later • Evaluation • Unwanted handouts
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
Part I Objectives • Learn the basic structure of papers • Develop an approach to reading papers • Learn how to interpret an article citation
The Basic Parts • Title • Abstract • Introduction • Methods • Results • Discussion • References
Read In This Order • Title • Abstract • Introduction/ Discussion • Methods/ Results
The discussion section occurs before the author presents the results of the study. • True • False
Which occurs first in a scientific journal article? • Abstract • Discussion • Introduction • Methods • Results
Abstract • Summarizes • Often only part read • Don’t act on abstracts alone • Structured abstracts are norm • Background • Methods • Results • Conclusions
Introduction • Context • What is known • Supporting literature (citations) • Gaps in literature • The research question • Newness • Relevance to field
Methods • Steps taken to • gather data • analyze data • Statistical methods • Not a “cookbook” • Replicable
Results • Report of data • Tables and graphs • Statistical results • No interpretation
Discussion • Interpretation of results • Answer to research question • Goals met? • Often includes • relation to previous research • limitations • future directions
Which should allow other researchers to replicate the study? • Abstract • Discussion • Introduction • Methods • Results
Limitations of the study are found in the… • Abstract • Discussion • Introduction • Methods • Results
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
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):517-519. Journal Volume Number Issue Number Researcher’s Article
Which cannot be determined from a reference list citation? • Title of the journal • Title of the journal article • Number of pages in the journal • Number of pages in the journal article • None of the above
Whether marijuana use causes lung cancer is still unknown and will likely be a subject of research in the next 5 years. • True • False
Part II Objectives • Learn the common study types • Be able to extract the research question • Be able to identify an article’s study type • Be able to determine the conclusions
Outline For This Section • Focus on 4 study designs • Case-control • Cohort • Randomized Control Trial • Review • Narrative • Systematic • Meta Analysis
“3 questions to get your bearings” * * - Greenhalgh, T. (2006). How to read a paper: the basis of evidence-based medicine. Malden, MA: Blackwell • What was the research question? • What was the research design? • 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
Study Designs Primary Literature Observational Case-Control Cohort Experimental Randomized Control Trial Secondary Literature Narrative (Subject/Journalistic) Reviews Systematic Review Meta Analysis
Case-Control Patients with a disease or exposure --compared to-- Similar group without disease or exposure Best uses Rare conditions Diseases or conditions that may take a long time to develop
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
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), 478-481. • Look at article: • Last sentence in Introductory area = research question • First paragraph in methods = research design
Why did the authors match cases and controls by the type of service mothers received?* • To reduce socioeconomic differences • To examine whether the cancer was related to infectious disease exposures • To decide if chemical disinfectants used to clean wards caused cancer • All of the above * -see page 879
Cohort • Two groups compared over time • One group with “exposure”, the other without the “exposure” • Best used: • when exposures can’t be controlled • when outcomes occur infrequently • when RCT is not ethical
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:10.1136/bmj.38142.554479.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 =
When was there enough evidence from this study to show the link between smoking and lung cancer? • 1954 • 1966 • 1978 • 1991
Randomized Control Trial A treatment group is compared to a control group Group members are assigned randomly Best uses: Drug therapies Medical treatments
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)194-199. • Look at the article: • The last paragraph of the introduction - research question • The last paragraph of the introduction - research design • Study flow chart - pg. 196
25,000 UM students were recruited by emailHow many UM students ended up in the intervention group? 1. 24,007 2. 2,407 3. 257 4. 107 5. 7
30 What percent of RealU participants had 30 days of no smoking at week 30? • 100% • 80% • 60% • 40% • 20% • none
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
Systematic Review • Reproducible methods to find and select articles are included • Should include both inclusion and exclusion criteria • Why? Decrease author bias
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:10.1016/j.vaccine.2008.09.036 • Look at article: • Pg. 2, Section 3.1, first paragraph = research question • Pg. 3, Section 4.1, first to third paragraphs = research design
30 It is recommended that HPV vaccine be given as a 3 shot series. How much do 3 doses of vaccine cost? • $500-$1000 • $300-$500 • $200-$300 • $100-$200
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
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
* - 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?
Thanks for your attention • We will post these slides on the Student Portal on the Norris Medical Library website • Contact us with questions • Joe Pozdol – pozdol@usc.edu • Evans Whitaker – ewhitake@usc.edu • Please complete evaluations!
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)194-199. Doll, R., Peto, R., Boreham, J., & Sutherland, I. (2004). Mortality in Relation to Smoking: 50 years' observations on male British doctors. BMJ, doi:10.1136/bmj.38142.554479.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, 372-383. 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), 490-495. Greenhalgh, T. (2006). How to read a paper: the basis of evidence- based medicine. Malden, MA: Blackwell. Guyatt, G., Rennie, D. (eds.). (2001). User’s guides to the medical literature: essentials of evidence-based clinical practice. Chicago: AMA Press.
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), 478-481. 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). 93,722-777. Peled, R. Carmil, D., Siboni-Samocha, O., & Shoham-Vardi, I. (2008). Breast cancer, psychological distress and life events among young women. BMC Cancer, 8, 245-250.