Selection bias is a term used in research and statistics to describe a situation where a sample of data is not representative of the population it is meant to represent. This can occur when certain groups of people or data points are overrepresented or underrepresented in the sample, leading to inaccurate or biased conclusions. Synonyms for selection bias include sampling bias, participant bias, measurement bias, and allocation bias. Each of these terms refers to a specific type of bias that can affect the validity and reliability of research findings. By understanding the different types of selection bias, researchers can design studies that are more accurate and representative of the population they are studying.