valikuhälve

Valikuhälve, often translated as selection bias, is a systematic error that occurs in scientific research when the method of sampling subjects or data causes the study group to be unrepresentative of the target population. This bias can arise from various factors, including how participants are recruited, how data is collected, or how a study is designed.

One common form of selection bias is volunteer bias, where individuals who volunteer for a study may differ systematically from those who do not, potentially leading to results that are not generalizable. Another is attrition bias, which occurs when participants drop out of a study at different rates between the intervention and control groups, or when the reasons for dropping out are related to the study's outcome.

Self-selection bias can also occur when individuals choose whether or not to participate in a study, leading to a sample that is not random. For example, in online surveys, individuals who are more technologically savvy or have stronger opinions might be more likely to respond.

The presence of selection bias can significantly impact the validity of research findings. If the sample is not representative of the population it is intended to describe, the conclusions drawn from the study may be inaccurate or misleading. Researchers employ various strategies to minimize selection bias, such as using random sampling techniques, ensuring comparable groups, and carefully analyzing reasons for participant attrition. Rigorous study design and careful consideration of potential sources of bias are crucial for obtaining reliable research outcomes.