Selective Attrition in Psychology Experiments

What Is Selective Attrition?

Selective attrition in psychology experiments refers to the tendency of some participants to be more likely to drop out of a study than others. This can lead to a biased sample and affect the validity of the results.

Causes of Attrition

Several factors can contribute to selective attrition, including:

• Motivation: Participants may lose interest in the study or find it too demanding.
• Mobility: Participants may move away or otherwise become unavailable to continue participating.
• Morbidity: Participants may become ill or incapacitated, making it difficult or impossible to continue.
• Mortality: Participants may die before the study is completed.

Attrition Bias

Selective attrition can lead to attrition bias, which occurs when the participants who drop out of a study are different from those who remain. This can result in a biased sample that does not accurately represent the population of interest.

Threats to Validity

Selective attrition can threaten the validity of a study by:

• Biasing the sample: The sample may no longer be representative of the population of interest.
• Reducing statistical power: The smaller sample size may make it more difficult to detect statistically significant differences.
• Introducing confounding variables: The reasons why participants drop out may be related to the variables being studied, which can confound the results.

Preventing Selective Attrition

Several strategies can be used to prevent selective attrition, including:

• Recruiting a diverse sample: A diverse sample is less likely to experience attrition due to factors such as mobility or morbidity.
• Providing incentives: Offering incentives, such as gift cards or cash, can help to motivate participants to stay in the study.
• Minimizing the burden of participation: Making the study as convenient and easy to participate in as possible can help to reduce attrition.
• Staying in touch with participants: Regularly contacting participants can help to remind them of the study and encourage them to stay involved.

Conclusion

Selective attrition is a common problem in psychology experiments. However, it can be prevented by taking steps to recruit a diverse sample, provide incentives, minimize the burden of participation, and stay in touch with participants.