Bias is a tendency to favor one idea, group, or viewpoint over another. It can influence how people think, decide, or judge situations. Bias can be conscious or unconscious.

A teacher, employer, or reader may interpret information differently because of bias. News reports, advertisements, or social media posts may also show bias in how information is presented. Bias can affect decisions in areas such as hiring, grading, or selection.

Bias is studied in psychology and social science. It is measured in research and surveys.