How to Read a Paper - PowerPoint

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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
SECTIONS OF A PUBLISHED
SCIENTIFIC PAPER
          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.


  1. True
  2. False
       Which occurs first in a
      scientific journal article?


1.   Abstract
2.   Discussion
3.   Introduction
4.   Methods
5.   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?


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


1.   Abstract
2.   Discussion
3.   Introduction
4.   Methods
5.   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?


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
 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
PART II
TYPES OF SCIENTIFIC PAPERS
         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
  o Case-control
  o Cohort
  o Randomized Control Trial
  o Review
    • Narrative
    • Systematic
    • Meta Analysis
 “3 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
         Study Designs
•Primary Literature
 oObservational
  • Case-Control
  • Cohort
 oExperimental
  • Randomized Control Trial
•Secondary Literature
 oNarrative   (Subject/Journalistic)
  Reviews
 oSystematic Review
 oMeta Analysis
              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
          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?*
                                                     * -see page 879
1.   To reduce socioeconomic
     differences                                             25% 25% 25% 25%

2.   To examine whether the
     cancer was related to
     infectious disease exposures
3.   To decide if chemical
     disinfectants used to clean
     wards caused cancer




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                                                                                     ...
                                                                        ..
4.   All of the above




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                                                                To
             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
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?

1.   1954
2.   1966                        25%     25%    25%   25%


3.   1978
4.   1991


                                54




                                         66




                                                 78




                                                        91
                              19




                                       19




                                               19




                                                      19
    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:
   o The last paragraph of the introduction - research question
   o The last paragraph of the introduction - research design
   o Study flow chart - pg. 196
25,000 UM students were recruited by email
  How many UM students ended up in the
           intervention group?

  1.   24,007
  2.   2,407
  3.   257
  4.   107
  5.   7
     What percent of RealU participants had
      30 days of no smoking at week 30?

1.   100%
2.   80%
3.   60%
4.   40%         30

5.   20%
6.   none
                                0%        0%        0%        0%        0%        0%




                                                                              ne
                                      %



                                                %



                                                          %



                                                                    %
                           0%


                                     80



                                               60



                                                         40



                                                                   20


                                                                             no
                          10
  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
It is recommended that HPV vaccine be
 given as a 3 shot series. How much do
         3 doses of vaccine cost?
 1.   $500-$1000
 2.   $300-$500
 3.   $200-$300
 4.   $100-$200
         30
                      0%          0%         0%         0%

                   $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
                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
ADDITIONAL SLIDES
                                 What kind of
                                                                                                                    Identifying
     Article Type                question is it                 Strengths                    Weaknesses
                                                                                                                  Characteristics
                                  good for?
Case-Control                  -Rare disorders or          -Short time frame to            -Susceptible to bias   -Cross sectional
(Herbst, 1971)                conditions                  examine                         -Limited validity
(Peled, 2008)                 -Slow developing            correlations
                              disorders                   between disorder
                              -Causation*                 and other factors


Cohort**                      - Prognosis                 - Feasible when                 -Susceptible to bias   -Longitudinal
(Doll, et al, 2004)           -Causation*                 studying conditions             -Limited validity      -Usually
(Metcalf, 2008)                                           or exposures over               -May require large     prospective
                                                          which the                       groups, long           -Can be
                                                          investigator has no             durations, great       retrospective (less
                                                          control                         cost                   cost)
Randomized Control            -Drug treatment             -Strong level of                -Feasibility (e.g.     -Randomization
Trial (RCT)                   -Medical                    evidence                        Ethical limitations)   method -
(An et al, 2008)              interventions               -Low susceptibility             -Generalizability**    Experimental and
(Gordon, 1997)                                            to bias                                                control groups
Systematic Review             -Drug treatment             -Low susceptibility             -Many topics have      -Methods section
(Techakehakij,2008)           -Medical                    to bias                         no systematic          has explicit
(Gallicchio, 2008)            interventions               -Strongest level of             review                 information about
                                                          evidence                                               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?
     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.