Selection attrition is the loss of participants from a study before the study is completed. This can happen for a variety of reasons, such as:
* Participants may drop out of the study because they are no longer interested in participating.
* Participants may move away or become too busy to continue participating.
* Participants may experience health problems or other life events that make it difficult to continue participating.
Selection attrition can bias the results of a study if the participants who drop out are different from the participants who remain in the study. For example, if a study is looking at the effects of a new drug, and the participants who drop out are more likely to have side effects from the drug, then the study may underestimate the true rate of side effects.
History
History refers to events that occur outside of the study that may influence the results of the study. For example, if a study is looking at the effects of a new teaching method, and there is a change in the curriculum during the study, then the change in the curriculum may affect the results of the study.
It is important to consider selection attrition and history when designing and conducting a study in order to minimize the risk of bias.
Here are some tips for minimizing the effects of selection attrition:
* Recruit a representative sample of participants.
* Make sure that the study is designed in a way that is interesting and engaging for participants.
* Follow up with participants who drop out of the study to find out why they dropped out.
Here are some tips for minimizing the effects of history:
* Conduct a pilot study to identify potential confounding variables.
* Control for confounding variables in the study design.
* Collect data on potential confounding variables.
By considering selection attrition and history, researchers can help to ensure that their studies produce valid and reliable results.