Bias refers to a systematic deviation of results or inferences from the truth, or the state of having a preference or inclination for a particular individual or group that interferes with impartial judgment. Bias can manifest in many ways, including in decision-making, research, and communication. In this article, we will explore the definition of bias, provide five examples, and conclude with a quiz to test your understanding of the concept.
Definitions:
- Confirmation bias: The tendency to interpret new information as confirmation of one’s existing beliefs or hypotheses.Selective exposure: The tendency to seek out information that confirms one’s existing beliefs and avoid information that contradicts them. Selective memory: The tendency to remember information that confirms one’s existing beliefs and forget information that contradicts them. Selective interpretation: The tendency to interpret ambiguous information in a way that confirms one’s existing beliefs.
Definitions (Confirmation Bias)
Selective exposure: The tendency to seek out information that confirms one’s existing beliefs and avoid information that contradicts them.
Selective memory: The tendency to remember information that confirms one’s existing beliefs and forget information that contradicts them.
Selective interpretation: The tendency to interpret ambiguous information in a way that confirms one’s existing beliefs.
- Selection bias: The bias introduced by the selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed.
Selection bias is a type of error that occurs when a sample of individuals or cases is chosen for a study in a way that is not representative of the population from which the sample is drawn. Selection bias can lead to incorrect conclusions or invalid results.
Definitions (Selection Bias)
- Selection bias: the process by which a sample of individuals or cases is chosen for a study in a way that is not representative of the population from which the sample is drawn.
- Sampling bias: a specific type of selection bias in which a sample is collected in such a way that certain individuals or groups are more or less likely to be included.
- Confirmation bias: a type of cognitive bias in which a person tends to seek out, interpret, and remember information in a way that confirms their preexisting beliefs or hypotheses.
- Self-selection bias: a type of selection bias that occurs when individuals are allowed to choose whether or not to participate in a study, leading to a sample that is not representative of the population.
- Observer bias: a type of bias that occurs when the person conducting a study unconsciously influences the results, for example by treating certain individuals differently.
- Examples:
- A study on the effectiveness of a new drug is conducted on patients at a single hospital. However, the population of patients at that hospital may be different from the population of patients in general, leading to selection bias.
- A study on the relationship between diet and heart disease is conducted using data from volunteers who have chosen to participate in the study. Self-selection bias may lead to a sample that is not representative of the general population.
- A researcher studies the relationship between a certain genetic variant and a disease. They only include individuals who have the genetic variant, therefore creating a selection bias since people with the variant make up only a small percentage of the general population
- A study of crime rates in a city is conducted by interviewing individuals on the street. Because individuals who are more likely to be victimized may be less likely to be willing to speak with the researcher, selection bias may lead to an underestimation of crime rates.
- A study on the effectiveness of a new teaching method is conducted by selecting only the best performing students from a school. This is a selection bias because, instead of being representative of the school population, it is a highly selective sample of it.
- Observer bias: Observer bias, also known as experimenter bias, is a type of bias that occurs when the researcher’s expectations or hypotheses influence the outcome of a study. This bias can occur in a variety of ways, such as through the selection of subjects, the design of experiments, or the interpretation of data.
One common example of observer bias is the placebo effect. In a clinical trial, if the researcher expects a certain treatment to be effective, they may unconsciously communicate this expectation to the subjects through nonverbal cues or other subtle means. As a result, the subjects may report feeling better even if the treatment itself had no actual effect.
Another example of observer bias is the experimenter-expectancy effect. This occurs when a researcher’s expectations about the outcome of an experiment influence the data they collect. For example, a researcher may unconsciously cue a subject to give a certain response, or may interpret ambiguous data in a way that confirms their hypotheses.
A third example is the observer-induced effect, which occurs when the observer’s presence affects the behavior of the subject being observed. For example, in a study on animal behavior, the researcher may inadvertently scare the animals and affect their normal behavior. Similarly, in human studies, the researcher’s presence may change the subject’s behavior, such as affecting the way they interact with their surroundings or other people.
A fourth example is the “Hawthorne effect”, occurs when the knowledge of being studied changes the behavior of the subjects. For example, a group of workers who are studying their productivity in an experiment may increase their productivity due to the fact they know they are being observed.
Finally, the halo effect is another example of observer bias. This occurs when a researcher forms a positive or negative impression of a subject based on one characteristic, such as physical appearance, and then unconsciously applies that impression to their evaluation of the subject’s other traits. For example, a researcher may think a subject is smart because they are physically attractive, and then unconsciously grade them more leniently on a test.
- Representation bias: Representation bias, also known as sampling bias or selection bias, refers to the phenomenon in which a sample of data used to make inferences about a population is not representative of that population. This can occur for a variety of reasons, including nonrandom sampling, measurement error, or data missingness. Representation bias can lead to inaccurate or unreliable inferences and conclusions and can be a major threat to the validity of research findings.
Definition: Representation bias occurs when a sample of data used to make inferences about a population is not representative of that population.
Examples:
Nonrandom sampling: Suppose a researcher wants to study the attitudes of high school students towards a new school policy. They decide to survey only the students in the honors classes, thinking that these students will be the most likely to have opinions on the policy. However, this method of sampling is not random, and the attitudes of the honors students may not be representative of the attitudes of all high school students.
Measurement error: Suppose a researcher wants to study the effectiveness of a new drug for treating depression. They conduct a study in which patients with depression are randomly assigned to either receive the new drug or a placebo. However, the researcher uses a measurement tool that is not valid or reliable to assess the patients’ depression symptoms. This measurement error can lead to representation bias, as the results of the study may not accurately reflect the true effectiveness of the drug.
Data missingness: Suppose a researcher wants to study the relationship between income and happiness. They survey a large sample of individuals and ask them about their income and happiness levels. However, some of the individuals do not respond to the survey, and their income and happiness levels are missing from the data. This missing data can lead to representation bias, as the individuals who did not respond to the survey may have different income and happiness levels than the individuals who did respond.
Self-serving bias: The tendency to attribute successes to oneself and failures to external factors. Self-serving bias refers to the tendency for individuals to attribute their successes to internal factors, such as ability or effort, while attributing their failures to external factors, such as luck or circumstance. This bias can manifest in a variety of ways and can have significant consequences for both individuals and organizations.
Definitions:
Attribution theory is the psychological theory that explains how people make judgments about the causes of their own and others’ behavior and events.
Examples:
An individual who excels at their job may attribute their success to their hard work and intelligence, while blaming their failures on poor management or a difficult work environment.
A student who receives a good grade on a test may attribute their success to their own studying and preparation, while blaming a poor grade on the difficulty of the test or the poor teaching of the instructor.
A football player who performs well in a game might credit their success to their training and dedication, while blaming their poor performance on the poor condition of the field.
A business leader who leads a successful company may attribute the company’s success to their own leadership and vision, while blaming the company’s failures on factors outside of their control such as the economy.
An individual who makes a good investment decision may attribute the success to their own research and analysis, while blaming a poor investment decision on market conditions or bad luck.
Examples:
- Confirmation bias in politics: A person who identifies as a conservative may only seek out news sources that align with their political beliefs, and therefore may have a confirmation bias towards conservative views.
- Selection bias in medical research: A study on the effectiveness of a new drug to treat high blood pressure is conducted, but only includes participants of a certain age, gender, or race. This can lead to selection bias, as the results may not be generalizable to the larger population of individuals with high blood pressure.
- Observer bias in the criminal justice system: A police officer may be more likely to suspect and arrest individuals of a certain race or socioeconomic background based on their preconceptions, leading to observer bias.
- Representation bias in the media: News outlets may disproportionately cover certain stories or individuals, leading to a representation bias in the information being shared with the public.
- Self-serving bias in the workplace: An employee may attribute their successes to their own abilities and hard work, but attribute any failures to external factors such as bad luck or their colleagues’ mistakes.
Quiz:
- What is Confirmation bias?
- What is Selection bias?
- What is Observer bias?
- What is Representation bias?
- What is Self-serving bias?
- In which field is Confirmation bias particularly relevant?
- In which field is Selection bias particularly relevant?
- In which field is Observer bias particularly relevant?
- In which field is Representation bias particularly relevant?
- In which field is Self-serving bias particularly relevant?
Answers:
- Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms one’s preexisting beliefs or hypotheses.
- Selection bias is the bias introduced by the selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed.
- Observer bias is the tendency for the expectations or preconceptions of the observer to influence the observations made.
- Representation bias is the tendency for a sample to disproportionately or inadequately represent certain subgroups of the population being studied.
- Self-serving bias is the tendency to attribute successes to oneself and failures to external factors.
- Confirmation bias is particularly relevant in the field
