Recall bias is a type of cognitive bias that occurs when someone’s memory is affected by what they expect to find, or what they want to remember. This article will discuss the impact of recall bias in studies and the best ways to avoid creating this bias.

What is Recall Bias

Recall bias is a statistical phenomenon that occurs when a person’s memory is distorted by their current state of mind. When this happens, the person’s recollection of past events will be skewed and possibly inaccurate. 

The most common example of recall bias is when people who have recently suffered an injury or illness assess the risk of developing cancer in the future. In this case, people who have suffered an injury or illness are more likely to believe that they are at risk of getting cancer primarily because they experience symptoms related to cancer (such as fatigue). This can then influence their memories of past events.

It is also a type of selection bias where the respondents of a survey are more likely to have certain characteristics than non-respondents. For example, if you asked people who have been arrested in the last year whether they had ever been arrested before, you’d expect them likely to say “yes” unlike the people who have not been arrested at all.

Read: Research Bias: Definition, Types + Examples

In other words, recall bias is a form of self-selection. When you’re conducting research and asking people to recall things from their memory, there’s always the possibility that they’ll be more likely to report having remembered something than not remembering it.

For example, let’s say you’re doing research on how people use the Internet. You might ask them to complete a survey about their habits, and then ask questions about what they did in the past week (or month).

They might tell you that they went on Facebook, but not mention that they also went on Twitter or Instagram. This means that your results will be skewed because people are more likely to remember things that happened recently than events from months ago and if those events happened with social media apps, then your study will underestimate how much time people spend on those sites

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

Difference between Recall Bias and Recall Limitation

Recall bias is when the results of a study are skewed due to a subject’s memory. For example, if you wanted to know how many people have a certain disease and you asked them to remember if they’d had it within the past five years, there’s a good chance some people would forget whether or not they did.

Recall limitation is when your memory is affected by time. You may use clues from recent events or experiences to help you determine what happened in the past, even if it’s not accurate. For example, if you’re trying to remember what happened on your last vacation, you might try thinking about what happened last weekend instead because that’s fresher in your mind.

Recall limitation is also a problem that can occur when you are gathering information from people.  Recall limitation happens when people have trouble remembering specific information because there was so much going on at once, or because they didn’t realize how important it was at the time.

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

What Type of Study Design is Most Prone to Recall Bias?

Recall bias is a problem for case-control studies.

In this type of study, researchers gather information about participants by asking them questions. They then compare that information with data gathered from a control group (a group of people who did not experience the specific condition or event under study) and this can happen because the people who choose to participate in a study have different experiences than those who do not.

For example, let’s say you’re looking to study the prevalence of car accidents among teenagers and you want to see if there’s a link between cell phone use while driving and accident rates. The first step would be to create two groups: one consisting of teenagers who have had at least one car accident and another consisting of teenagers who have never had an accident. 

The next step would be to ask both groups about their cell phone usage while driving: whether they usually text, call, or use social media while driving; how many times per week they do so; etc. Then you’d compare answers between the two groups to see if there was any difference between them. 

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

For example, if those who reported using their phones more frequently also reported having more accidents than those who used their phones less often or not at all. This type of study design is prone to recall bias because it depends on participants accurately remembering past events when answering questions about them.

Other High-Risk Factors for Recall Bias

  • The participant has a vested interest in the outcome of the study
  • The participant’s memory was affected by alcohol or drugs at the time of the event being recalled
  • The age of the participants
  • The length of time between when an event occurred and when it was reported
  • If the participant has a strong emotional attachment to the event.

Examples of Recall Biases

Example 1

For example, if you read an article about someone who was arrested for drunk driving and later go to a bar with your friends, you’d more likely think of the person as a drunk than you would have otherwise. In this case, your memory of the event has been influenced by your exposure to information about it after the fact.

Example 2

If you’re conducting a study on how people feel about a new movie, and you only ask people who’ve seen it already (or who have plans to go see it soon), then you’ll get a biased sample. The people who have seen it will all say they liked it, while those who haven’t will be more likely to say they didn’t like it. That’s because those who saw the movie and liked it will be more willing to talk about it, while those who didn’t are more likely to avoid talking about something they didn’t like.

Read: What is Experimenter Bias? Definition, Types & Mitigation

Example 3

If you’re working on a case-control study about eating habits and cancer risk, you might ask people about their eating habits at some point in the past (or even just recently). They may not remember those habits accurately or may have forgotten them entirely. This could lead them to tell you things that aren’t true which would affect your ability to come up with accurate conclusions about whether or not certain foods cause cancer.

Implications of Recall Bias

  1. Recall bias can lead to false conclusions about a population since it does not account for all of the data that may have been collected.
  2. It can also result in the failure to recognize trends or patterns in data, which may be important for decision-making.
  3. It can lead to a lack of trust in research findings.
  4. It can also cause a lack of respect for scientific evidence due to personal biases affecting recall bias.

Tips to Avoid Recall Bias

When you’re designing a study, there are several things you can do to minimize the risk of recall bias:

  1. Use random sampling techniques to gather information about a population instead of relying on self-reported data from one or more members of that population.
  2. Be aware that memory tends to fade with time, so your recollection may be biased by what you remember happening and what actually did happen.
  3. Ask questions that don’t require recall of past events. For example, instead of asking “How often have you used Facebook in the last month?”, ask “What was your first thought when you woke up this morning?”.
  4. Ask open-ended questions where participants can provide their own answers. This will give you more information about how people feel or think about something, rather than just what they remember from their past experiences with it.
  5. Make sure that participants understand what is being asked before they respond so they don’t misinterpret it as something else and answer incorrectly based on that misunderstanding instead.

Read: Sampling Bias: Definition, Types + [Examples]


Recall bias is a common problem in research. It occurs when someone’s memory of events influences their responses to survey questions.

The implication of the bias is that you may not be getting an accurate picture of what people are actually thinking or feeling. This can lead to faulty conclusions and inaccurate predictions about the future.

It is important for researchers to find appropriate measures to reduce the recall bias effect to avoid inaccurate results in their studies. 

  • busayo.longe
  • on 7 min read


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