Are there biases in the world of scientific publication? Indeed, one comes across biases in the publishing industry such as publication bias, time lag bias, multiple publication bias, location bias, citation bias, language bias, outcome reporting bias, confirmatory bias, and funding bias. This tutorial briefly explains what each of these biases is and how you can address them. Additionally, the SlideShare will enlighten you about the causes and effects of these biases, and why you should proactively oppose such prejudices.

1. Publication and reporting biases and how they
impact publication of research
Helping you get published

2. Publication and reporting biases and how they impact publication of research
“In a desert prison, an older prisoner befriends a new arrival. The young
prisoner talks constantly about escape, spinning plan after plan. After a
few months, he makes a break. He’s gone a week; then the guards drag
him back. He’s half-dead, crazy with hunger and thirst. He wails how
awful it was to the old prisoner: endless stretches of sand, no oasis,
failure at every turn. The old prisoner listens for while, then says, “Yep. I
know. I tried those escape plans myself, 20 years ago.” The young
prisoner says, “You did? Why didn’t you tell me?” The old prisoner
shrugs” “So who publishes negative results?”
”

3. Publication and reporting biases and how they impact publication of research
This anecdote aptly illustrates a problem that plagues scientific
literature—publication bias or reporting bias.1
Publication bias refers to a phenomenon in scientific reporting
whereby authors are more likely to submit and journal editors
are more likely to publish studies with “positive” results (i.e.
results showing a significant finding) than studies with
“negative” (i.e. supporting the null hypothesis) or
unsupportive results.2
As a result of such a bias, important—albeit negative—results
(e.g., a study showing that a new treatment is ineffective) may
never reach the larger scientific community.3

4. Publication and reporting biases and how they impact publication of research
This bias toward publishing studies with positive results is
just one of the many different types of publication-related
biases. As these biases influence publication decisions, it is
important that you understand
what causes these biases
the different types of biases, how they impact publication
decisions, and how to address them
the need to counter publication and reporting biases

5. Publication and reporting biases and how they impact publication of research
Causes of bias
Reporting and publication biases are caused by many different factors. We’ve listed
some of the main causes of these biases below:
1. Many studies remain unpublished because researchers do not submit their work
for publication, thinking that journals will reject their papers because they do not
have positive or significant results to report. This submission-related bias has been
termed the file drawer problem.4
2. Journals may be biased toward positive results because negative results are less
likely to be cited and can thus lower a journal’s impact factor.
3. Study sponsors or funding sources may be biased towards results that favour their
interests; it has been found that sponsors may withhold the publication of
unfavourable results and that industry-funded studies have led to positive results
far more often than studies that are funded or conducted by independent
agencies.5,6

6. Publication and reporting biases and how they impact publication of research
Different biases and how you can address them
The table in the next few slides lists different types of
publication and reporting biases that have been found to
exist in scientific literature.1,7-11
It also offers some suggestions for addressing the different
types of biases. It is best to address these biases directly,
possibly while discussing the importance of the study in your
cover letter to the journal editor.

7. Publication and reporting biases and how they impact publication of research
Type of bias What it means How to address this bias
Publication bias Studies with positive results are more likely to be Describe the specific problem that your
accepted for publication than studies with negative study results will help address. Point out
results. that your negative results could help
counter publication bias12 (in fact, there
are now journals that exclusively publish
negative results13) and specify the
outcome or views that your study can
potentially change.
Time lag bias Studies with positive findings are likely to be State why you think your study should
published faster than studies with negative findings. be published without delay (e.g.,
because the results could warrant
suspension of further trials or could
affect how things are being done in
practice).
Multiple publication bias Multiple publications are more likely to be If you have published a paper discussing
generated from a single set of positive or supportive a set of positive results, do not publish
results than from a set of negative or unsupportive another paper using the same set of
results results (unless you are offering a
radically different perspective or
analysis; always cross-reference the first
publication).

8. Publication and reporting biases and how they impact publication of research
Type of bias What it means How to address this bias
Location bias Studies that report positive results have First, do not hesitate to submit your
a greater chance of being published in paper to a journal with a high-impact
widely circulated, high-impact journals factor. Researchers have found that one
than do studies with negative results. of the main reasons for location bias is
that authors send negative results to
low-impact factor journals, and not
necessarily because journals are more
likely to reject these studies.14,15 Second,
when submitting to a high-impact
journal, explain how the paper fits the
journal’s scope and target audience,
why the negative results are important,
how the results challenge existing
knowledge, and why it is important that
your research reaches a wide audience.
Citation bias Researchers are more likely to cite If you come across negative results
positive study results than negative related to your study, be sure to
study results. mention them in your paper. Do not cite
studies that only support your own
results, as this could lead peer reviewers
to suspect bias.

9. Publication and reporting biases and how they impact publication of research
Type of bias What it means How to address this bias
Language bias The language in which a study is Describe how your study results are of
published depends on whether the relevance to a global audience and
study has positive or negative results; hence should be published in an
studies with positive results are more international journal that reaches out to
likely to be published in English- this audience.
language journals.
Outcome reporting bias Researchers working on a study in which Report any outcome that is relevant to
multiple outcomes were measured are your study, whether it is positive or
more likely to report positive outcomes negative.
than negative outcomes.
Confirmatory bias Findings that conform to a person’s Relate your study to a previous study
(e.g., peer reviewer’s or journal editor’s) published in the journal. Explain that
beliefs and hypotheses are more likely your study results may go against
to be recommended for publication or previously/widely held beliefs.
published. Emphasize how your study results can
address an issue or change existing
perspectives.

10. Publication and reporting biases and how they impact publication of research
Type of bias What it means How to address this bias
Funding bias Study conclusions are biased in favor of Ensure that your sponsors do not
the sponsors’ products; findings that go influence your study decisions—you
against the interests of study sponsors should have access to all study data,
never make it into print. should analyze the data and choose the
study methodology independently, and
should have the final say in preparation
and submission of the
manuscript.16Always disclose funding
sources and any conflict of interest.
Manuscripts disclosing any funding
source are more likely to be published
than those without such a disclosure.11

11. Publication and reporting biases and how they impact publication of research
Why you should proactively counter biases
Publication and reporting biases defeat the very purpose of research. By emphasizing the
publication of positive results, these biases have built “a systematically unrepresentative” body of
literature17 and have “led to scientific integrity being compromised.”18
This can have adverse consequences, such as ineffective or dangerous treatments, prolonged
suffering among patients, and wasted resources (See box: “Effects of publication bias”).
By countering publication and reporting biases, you can help maintain the integrity of scientific
literature—by submitting methodologically sound studies that have not yielded the expected
results; by highlighting the need to publish both negative and positive results; by conducting peer
reviews objectively and without prejudice; by refusing to allow funding agencies influence study
methodology, reporting of outcomes, or publication decisions.
A collective effort will ensure that published findings are more representative of all the completed
studies and can help maintain the integrity of scientific literature.

12. Publication and reporting biases and how they impact publication of research
Effects of publication bias
Effects of publication bias on literature Effects of publication bias on public health
• Positive study findings may dominate • In 1980, researchers who found an increased
published literature.17 death rate among heart patients treated with
• Since fewer negative results are published, a class 1 anti-arrhythmic did not publish their
there could be an overestimation of the study, considering this result to be a chance
efficacy of new treatments, social policies, or finding. Later, these drugs were found to
new devices, and an underestimation of their actually lead to increased mortality in heart
risks or drawbacks.3,11,19 patients. In 1993, the researchers
• Studies that find a treatment to be harmful acknowledged that this non-publication “was
may never be published.7 a good example of ‘publication bias’”; 20 they
admitted that had they reported their
findings 13 years earlier, they could have
saved lives.7,20
• A review of experimental studies examining
the adverse effects of cell phone use on
health revealed that industry-funded studies
were least likely to report a positive result.21

13. Publication and reporting biases and how they impact publication of research
References:
1. Sterne JAC, Egger M, Moher D. (Editors) (2008). Chapter 10: Addressing reporting biases in Cochrane Handbook
for Systematic Reviews of Interventions (eds. JPT Higgins and S Green). Version 5.0.1 [updated September
2008]. The Cochrane Collaboration.
2. Dickersin K (1990). The existence of publication bias and risk factors for its occurrence. Journal of the American
Medical Association, 263: 1385–1389.
3. McGauran N, et al. (2010). Reporting bias in medical research—a narrative review. Trials, 11: 37.
4. Rosenthal R (1979). The "file drawer problem" and tolerance for null results. Psychological Bulletin, 86(3): 638–
641. doi: 10.1037/0033-2909.86.3.638.
5. Bodenheimer T (2000). Uneasy alliance—clinical investigators and the pharmaceutical industry. New England
Journal of Medicine, 342: 1539–1544.
6. Bekelman JE, Li Y, Gross CP (2003). Scope and impact of financial conflicts of interest in biomedical
research. Journal of the American Medical Association, 289(4): 454–465.
7. Song F, Parekh S, Hooper L, Loke YK, Ryder J, Sutton AJ, et al (2010). Dissemination and publication of research
findings: An updated review of related biases. Health Technology Assessment, 14(8): iii,ix–xi.
8. Mahoney MJ (1977). Publication prejudices: An experimental study of confirmatory bias in the peer review
system. Cognitive Therapy and Research, 1(2): 161–175. doi: 10.1007/BF01173636.
9. Chopra SS (2003). Industry funding of clinical trials: Benefit or bias? Journal of the American Medical
Association, 290(1): 113–114.
10. Lesser LI, Ebbeling CB, Goozner M, Wypij D, Ludwig DS (2007). Relationship between funding source and
conclusion among nutrition-related scientific articles. PLoS Medicine, 4(1): e5.

14. Publication and reporting biases and how they impact publication of research
References:
11. Lee KP, Boyd EA, Holroyd-Leduc JM, Bacchetti P, Bero LA (2006). Predictors of publication: Characteristics of submitted
manuscripts associated with acceptance at major biomedical journals. Medical Journal of Australia, 184: 621–626.
12. Sridharan L & Greenland P (2009). Editorial policies and publication bias: The importance of negative studies (editorial
commentary). Archives of Internal Medicine, 169: 1022–1023.
13. Kotze JD, Johnson CA, O’Hara RB, Vepsäläinen K, Fowler MS (2004). Editorial. Journal of Negative Results—Ecology &
Evolutionary Biology, 1: 1–5.
14. Koricheva J (2003). Non-significant results in ecology: A burden or a blessing in disguise? Oikos, 102: 397–401.
15. Leimu R & Koricheva J (2004). Cumulative meta-analysis: A new tool for detection of temporal trends and publication
bias in ecology. Proceedings of the Royal Society of London, B271: 1961–1966.
16. International Committee of Medical Journal Editors. Uniform requirements for manuscripts submitted to biomedical
journals: Writing and editing for biomedical publication [Accessed: June 14, 2011] Available
from: http://www.ICMJE.org.
17. Rothstein HR, Sutton AJ, Borenstein M. (Editors) (2005). Chapter 1: Publication Bias in Meta-Analysis in Publication Bias
in Meta-Analysis: Prevention, Assessment and Adjustments (eds. HR Rothstein, AJ Sutton, and M Borenstein). John
Wiley & Sons Ltd.: Chichester, UK.
18. Editorial. The whole truth. New Scientist. May 1, 2004. Magazine issue 2445.
19. Scholey JM & Harrison JE (2003). Publication bias: Raising awareness of a potential problem in dental research. British
Dental Journal, 194: 235–237.
20. Editorial: Dealing with biased reporting of the available evidence. The James Lind Library. [Accessed: June 14, 2011]
Available from: www.jameslindlibrary.org.
21. Huss A, Egger M, Hug K, Huwiler-Müntener K, Röösli M (2007). Source of funding and results of studies of health effects
of mobile phone use: Systematic review of experimental studies. Environmental Health Perspectives, 115: 1–4.

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