Reporting bias is a type of selection bias that occurs when only certain observations are reported or published. Reporting bias can greatly impact the accuracy of results, and it is important to consider reporting bias when conducting research. In this article, we will discuss reporting bias, the types, and the examples.

What is Reporting Bias?

Reporting bias is a type of selection bias that occurs when the results of a study are skewed due to the way they are reported. Reporting bias happens when researchers or scientists choose to report only certain data, even though other data may exist that would have influenced their findings.

For example, if you were to conduct a study on the effects of eating chocolate on mice and only used mice from a particular region, then your results could be skewed because they would not be representative of all mice. Reporting bias can also occur when the data is manipulated before it’s reported, as in the case of cherry-picking or data mining.

This can result in unreliable or biased results reported by an organization or individual. The most common form of reporting bias is selection bias. This is when participants in a study are chosen based on their ability to influence the outcome or for other reasons that might create an inaccurate picture of reality.

Read: What is Participant Bias? How to Detect & Avoid It

Another reporting bias occurs when researchers do not report all the results of their studies. They may leave out information because they don’t think it’s important or because they want to make their findings seem more impressive than they are.

This is why there’s a field of science dedicated to trying to determine what happened in studies where there was reporting bias: a meta-analysis. A meta-analysis is an analysis of multiple studies on the same topic done by different researchers, which can help provide more insight into whether a particular finding is factual or not.

Read: Selection Bias in Research: Types, Examples & Impact

Types of Reporting Bias

1. Outcome reporting bias

Outcome reporting bias occurs when an outcome that was not originally planned for (or expected) is reported in favor of the hypothesis being tested. This can be due to either a conscious or unconscious decision made by the researcher.

For example, suppose you wanted to test whether eating more vegetables improves health outcomes. If you find that people who ate more vegetables were healthier than those who didn’t and then decide that this means eating vegetables improves health, you may have fallen victim to outcome reporting bias because it was never your intention to study how vegetables affect health outcomes.

2. Publication bias

Publication bias is another form of reporting bias where journals or other publications only print positive results from studies conducted on their topic(s). This means that only positive results are published, leading readers to believe that there’s no need for further research on the topic because all of the relevant evidence has already been collected. This can also lead to the “file drawer” phenomenon where negative results are not published because they will not contribute positively to the researcher’s reputation or career advancement.

Read: 21 Chrome Extensions for Academic Researchers in 2022

3. Knowledge reporting bias

Knowledge reporting bias refers to the fact that researchers may not report all their knowledge about a topic or experiment because they feel it isn’t important enough or doesn’t fit their hypothesis.

Here’s an example: let’s say two researchers are studying whether people feel healthier if they eat vegetables every day versus if they eat vegetables once or twice per week and one researcher finds no difference between eating vegetables daily vs. once per week, but the other did find a health improvement when people ate veggies daily versus once per week. The first researcher might decide not to report this finding and then prevent the readers from knowing that possibility.

4. Multiple (duplicate) publication bias

Multiple publication bias is when a study is published repeatedly either due to changes in methodology or because the same data is analyzed differently by different researchers. This can lead to false conclusions about the effectiveness of a treatment or program because it skews the results towards positive outcomes.

5. Time lag bias

Time lag bias occurs when a study is conducted with no follow-up measures, so it doesn’t get published until much later when someone revisits the topic and does another study on it (with follow-up data). When this happens, researchers are unable to determine whether or not there has been any change over time due to intervention or other factors because they don’t have any data from before intervention began.

6. Citation bias

Citation bias occurs when one researcher cites another researcher’s work as evidence for their argument without acknowledging that it was cited from someone else’s paper first; essentially making it look like they came up with an idea on their own instead of building off someone else’s work.

Explore: Citation Styles in Research Writing: MLA, APA, IEEE

Examples of Reporting Bias

Example 1

For example, if you were studying how many people with blue eyes wear glasses and found that only 40% of people with blue eyes wear glasses, then it could be because they didn’t include all the people with blue eyes in your study. It could also be because there are other factors at play that make fewer people with blue eyes wear glasses such as those who don’t wear glasses may not feel like wearing them.

Example 2

Reporting bias can also happen when someone running a survey or experiment asks leading questions. For example, instead of asking “Do you like eating bananas?” they might say “Bananas are delicious,” or instead of asking “Have you ever eaten bananas?” they might say “Wouldn’t it be nice if we could eat bananas every day?” The first question does not affect the outcome, but if someone answers yes to the second question, it is because they think they have to agree with the pollster’s statement.

Read: Undercoverage Bias: Definition, Examples in Survey Research

Example 3

If you ask people to rate their performance as a manager on a scale from 1 to 5, and then you ask them about their coworkers’ performance, they might tell you that all their coworkers are doing great (because they don’t want to look bad). This is an example of reporting bias because it skews the results of your study by making it seem like everyone is performing well when in reality, it may be that some people are doing poorly.

Effects and Implications of Reporting Bias

Reporting bias can lead to false conclusions being drawn from experiments and may even lead to harm for patients or subjects involved in a study. For example, if a researcher does not report all of their data, it could lead them to think that their treatment works better than it does.

This would result in them prescribing this treatment to patients who don’t need it or causing other researchers to replicate their experiment with incorrect results. When a study sample is selected based on reporting, the results are likely to be biased in favor of positive results: if people are more likely to report positive events than negative events, then they’ll also be more likely to not report at all.

Reporting bias can have serious implications for your survey and your business. If you’re trying to figure out whether your product/service is effective at solving problems for customers (or not), then reporting bias can make it hard for you to get an accurate lead on how well it works across different demographics and situations.

Read: Survey Errors To Avoid: Types, Sources, Examples, Mitigation

How to Prevent or Manage Reporting Bias

  1. Be honest with yourself about whether or not your results are statistically significant enough to be considered valid. If they are not, then don’t pretend they are.
  2. You can also try running some more experiments before publishing your findings so that there’s more evidence available for readers who might want more proof before believing what was found during your experiment.
  3. Consider using statistics or data to back up your claims whenever possible.
  4. You can also manage it by collecting and reporting data from additional sources to provide an alternative view of the data. This can be done by asking colleagues who have not been involved in the project to review the results for plausibility, or by running a second analysis that uses more conservative assumptions.

Read: Research Bias: Definition, Types + Examples


Reporting bias is a phenomenon in which the reporting of a study is biased by the researcher’s expectations of what they want to find and it can be caused by many factors. You must practice transparency in your research as that would help you better manage reporting bias.

  • busayo.longe
  • on 7 min read


You may also like:

What is Publication Bias? (How to Detect & Avoid It)

In this article, we will do a deep dive into publication bias, how to reduce or avoid it, and other types of biases in research.

7 min read
Selection Bias in Research: Types, Examples & Impact

In this article, we’ll discuss the effects of selection bias, how it works, its common effects and the best ways to minimize it.

8 min read
Recall Bias: Definition, Types, Examples & Mitigation

This article will discuss the impact of recall bias in studies and the best ways to avoid them during research.

7 min read
Projective Techniques In Surveys: Definition, Types & Pros & Cons

Introduction When you’re conducting a survey, you need to find out what people think about things. But how do you get an accurate and...

6 min read

Formplus - For Seamless Data Collection

Collect data the right way with a versatile data collection tool. Try Formplus and transform your work productivity today.
Try Formplus For Free