Question
Define selection bias
Answers
GPT-4o
Selection bias occurs when the sample collected for a study or analysis is not representative of the population intended to be analyzed. This bias arises during the selection process of the participants, leading to systematic errors in the results and ultimately making the findings invalid or skewed.
There are several ways selection bias can manifest:
1. **Self-Selection Bias**: When participants, rather than being randomly chosen, have the option to participate or not, leading those with specific characteristics or interests to be overrepresented.
2. **Survivorship Bias**: When only subjects that 'survived' a particular process are included in the analysis, ignoring those that didn't make it through the process.
3. **Sampling Bias**: When certain groups are more likely to be included in the sample than others, often due to the sampling method used.
4. **Attrition Bias**: When participants drop out of a study over time, and those who remain are different in important ways from those who leave.
5. **Exclusion Bias**: When particular groups are systematically excluded from the study.
Addressing selection bias typically involves careful design of the study, such as using random sampling methods, ensuring high follow-up rates, and employing statistical techniques to adjust for any biases identified.
There are several ways selection bias can manifest:
1. **Self-Selection Bias**: When participants, rather than being randomly chosen, have the option to participate or not, leading those with specific characteristics or interests to be overrepresented.
2. **Survivorship Bias**: When only subjects that 'survived' a particular process are included in the analysis, ignoring those that didn't make it through the process.
3. **Sampling Bias**: When certain groups are more likely to be included in the sample than others, often due to the sampling method used.
4. **Attrition Bias**: When participants drop out of a study over time, and those who remain are different in important ways from those who leave.
5. **Exclusion Bias**: When particular groups are systematically excluded from the study.
Addressing selection bias typically involves careful design of the study, such as using random sampling methods, ensuring high follow-up rates, and employing statistical techniques to adjust for any biases identified.