What is publication bias in clinical research?

Published on October 29, 2022 by Kassiani Nikolopoulou. Revised on February 15, 2023. Publication bias refers to the selective publication of research studies based on their results. Here, studies with positive findings are more likely to be published than studies with negative findings.

What is an example of publication bias in research?

Publication bias occurs when one type of study result is more likely to be published than another. For example, publishing results of studies that show a new treatment provides significant benefits, but not always publishing studies that show less or no benefit, will lead to publication bias.

What is an example of bias in clinical research?

For example, suppose the participants are allocated to receive either a standard drug or a new drug with the objective to assess side effects. If the patients with the worst side effects from the new drug did not return for follow-up and outcome recording, the results would most likely be biased.

How do you know if there is publication bias?

A subgroup analysis of moderators that includes published studies and unpublished studies are estimated and, if the effect-size estimate of published studies is greater than that of unpublished studies, then one can reasonably conclude publication bias is evident (Borenstein et al., 2011).

What is the difference between selection bias and publication bias?

Evidence selection bias occurs when a systematic review does not identify all available data on a topic. This can arise from publication bias, where data from statistically significant studies are more likely to be published than those that are not statistically significant.

Understanding Publication Bias in Research

What are some examples of publication bias?

What is publication bias also known as?

Publication bias is sometimes called the file-drawer effect, or file-drawer problem. This term suggests that results not supporting the hypotheses of researchers often go no further than the researchers' file drawers, leading to a bias in published research.

How can publication bias be avoided?

Bias can be minimized by (1) insisting on high-quality research and thorough literature reviews, (2) eliminating the double standard concerning peer review and informed consent applied to clinical research and practice, (3) publishing legitimate trials regardless of their results, (4) requiring peer reviewers to ...

What is the best test for publication bias?

Egger's test is commonly used to assess potential publication bias in a meta-analysis via funnel plot asymmetry (Egger's test is a linear regression of the intervention effect estimates on their standard errors weighted by their inverse variance).

What are the two methods of publication bias testing?

What are the most common biases in clinical trials?

There are five main forms of bias that are important to consider for clinical trials: Selection Bias, Performance Bias, Detection Bias, Attrition Bias, and Reporting Bias (Table 1) [1, 3].

Why is it important to avoid bias in a clinical study?

To succeed, a clinical research study must be fully impartial and free from human error. But researchers are humans, too – which means unintentional bias can seep into clinical research studys. This can, in many cases, potentially obscure trial results and render a study ineffective.

What are the consequences of bias in clinical trials?

Bias in clinical trials may be described as systematic errors that encourage one outcome over others. The potential effect of bias is that investigators will come to the wrong conclusions about the beneficial and harmful effects of interventions.

What type of bias is publication bias?

Publication bias is a type of reporting bias and closely related to dissemination bias, although dissemination bias generally applies to all forms of results dissemination, not simply journal publications.

Why is publication bias an issue?

In the presence of publication bias, belief in the relationship increases artificially and iteratively with each positive publication. This, in turn, diminishes the credibility of hypothesis testing because it is based on biased information, and calls into question the integrity of the entire experimental framework.

How is publication bias an ethical issue?

Apparently, publication bias poses serious threats to the integrity of scientific research. It prevents us from consuming objective, true, and unbiased research, and introduces much error in what we read and believe. Thus, publication bias and relevant topics should be addressed in research ethics modules and courses.

How many studies are needed for publication bias?

Second, investigators should use appropriate techniques to assess publication bias such as Egger's regression or symmetry of funnel plots whenever there are greater than 10 studies combined in a meta-analysis (with less than 10 the assessment methods are not very reliable).

What is the funnel test for publication bias?

If there is publication bias, then studies with low precision that have negative or non-significant results will be missing from the plot because they were not published, producing a funnel plot that is asymmetric. Identifying funnel plot asymmetry may therefore suggest the possibility of publication bias.

What is the risk of publication bias?

Specifically, the conclusions of the review may be compromised when decisions about how, when and where to report results of eligible studies are influenced by the nature and direction of the results. This is the problem of 'non-reporting bias' (also described as 'publication bias' and 'selective reporting bias').

Is publication bias intentional?

Bias may be introduced intentionally or unintentionally, consciously or unconsciously, into the process of research dissemination. 3,18 The dissemination profile of research may be influenced by investigators, study sponsors, peer reviewers, and journal editors.

Why is there a publication bias against null effects?

Publication bias can also arise from decisions of journal editors and peer reviewers to reject studies with null results because: “negative results have never made riveting reading”; the study may be similar to the peer-reviewer's own work; they may be biased against research in different fields; or because studies ...

Why might clinical scientists not disclose their datasets or methods after they are published?

The clinical trialists may fear that sharing the full analyzable data set will give other investigators who did not contribute to the conduct of the study an opportunity to publish additional analyses before the members of the study team have done so.

How can bias be removed from clinical trials?

To minimize or avoid performance bias, investigators can consider cluster stratification of patients, in which all patients having an operation by one surgeon or at one hospital are placed into the same study group, as opposed to placing individual patients into groups.

What is used to avoid bias in a clinical trial?

Blinding is an important practice for ensuring the validity of clinical research and reducing measurement bias. Blinding refers to a practice where study participants are prevented from knowing information that may influence them and affect the results of a trial.

Which of the following is used to avoid bias in a clinical trial?

Randomization is the process by which treatments are assigned to participants by chance rather than by choice. This is done to avoid any bias in assigning volunteers to get one treatment or another. The effects of each treatment are compared at specific points during a trial.