Joe Pozdol, MLIS
Evans Whitaker, MD, MLIS
Norris Medical Library
University of Southern California
2003 Zonal Ave.
Los Angeles, CA 90089-9130
Before We Begin…
• PowerPoint at www.usc.edu/nml under
Key Resources for Students
• Interactive questions
• Article later
• Unwanted handouts
Outline For Today
I. Parts of a paper
F. References (Bibliography)
II. Study types
III. Group work
SECTIONS OF A PUBLISHED
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
Read In This Order
The discussion section occurs
before the author presents the
results of the study.
Which occurs first in a
scientific journal article?
• Often only part read
• Don’t act on abstracts alone
• Structured abstracts are norm
• What is known
• Supporting literature (citations)
• Gaps in literature
• The research question
• Relevance to field
• Steps taken to
– gather data
– analyze data
• Statistical methods
• Not a “cookbook”
• Report of data
• Tables and graphs
• Statistical results
• No interpretation
• Interpretation of results
• Answer to research question
• Goals met?
• Often includes
– relation to previous research
– future directions
Which should allow other
researchers to replicate the study?
Limitations of the study are
found in the…
• 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)
• EndNote and RefWorks
Understanding Journal Article
Weiss, PA. Does smoking marijuana contribute to the risk of developing
lung cancer? Clinical Journal of Oncology Nursing. 2008;12(3):517-519.
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
4. Number of pages in the
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.
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 Randomized Control Trial
• Meta Analysis
“3 questions to get your bearings” *
1. What was the research
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
• Randomized Control Trial
Patients with a disease or exposure
Similar group without disease or exposure
• Best uses
o Rare conditions
o Diseases or conditions that may take a long
time to develop
• 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
4. All of the above
• 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
• Doll, R., Peto, R., Boreham, J., & Sutherland, I.
(2004). Mortality in Relation to Smoking: 50
years' observations on male British doctors.
• 50 years (and counting) Cohort Study of British
• 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
2. 1966 25% 25% 25% 25%
Randomized Control Trial
• A treatment group is compared to a
• Group members are assigned randomly
• Best uses:
– Drug therapies
– Medical treatments
Example: Smoking cessation
• 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
What percent of RealU participants had
30 days of no smoking at week 30?
4. 40% 30
0% 0% 0% 0% 0% 0%
• 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
• Reproducible methods to find and select
articles are included
• Should include both inclusion and exclusion
• Why? Decrease author bias
Example: Is HPV Vaccine
• Techakehakij, W., Feldman, R.D. (2008). Cost-
effectiveness of HPV vaccination compared to
Pap smear screening on a national scale: a
literature review. Vaccine,
• Look at article:
– Pg. 2, Section 3.1, first paragraph = research question
– Pg. 3, Section 4.1, first to third paragraphs =
It is recommended that HPV vaccine be
given as a 3 shot series. How much do
3 doses of vaccine cost?
0% 0% 0% 0%
$500-$1000 $300-$500 $200-$300 $100-$200
• 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
• Groups of 3
• Everyone in group gets same article (#1, 2, 3, OR 4)
• Spend 10 min. working together on questions
• Class discussion
What kind of
Article Type question is it Strengths Weaknesses
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
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
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• Contact us with questions
– Joe Pozdol – firstname.lastname@example.org
– Evans Whitaker – email@example.com
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• 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,
• 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.
• 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.