selectionbias

Selection bias occurs when the process of selecting participants or data for a study results in a sample that is not representative of the population of interest. This can lead to misleading or inaccurate conclusions. Several types of selection bias exist. Sampling bias, for instance, arises when the method used to obtain participants favors certain individuals over others, such as relying solely on volunteers or using a convenience sample that excludes specific groups. Attrition bias, or dropout bias, happens when participants who drop out of a study differ systematically from those who remain, potentially altering the study's outcomes. Another form is self-selection bias, where individuals choose whether or not to participate, and their decision is related to the outcome being studied. For example, a survey on job satisfaction might attract more responses from people who are either very happy or very unhappy with their jobs, skewing the results. Researchers must be aware of these potential pitfalls and employ strategies to minimize selection bias, such as using random sampling techniques and carefully considering exclusion criteria. Recognizing and addressing selection bias is crucial for the internal and external validity of research findings.