What is systematic error (bias) in research?

• A. Random variability in measurements
• B. Non-random, unidirectional error that threatens internal validity
• C. Measurement error without direction
• D. Errors that are easily identifiable and correctable

Answer: (B)

Systematic error, often referred to as bias, is defined as a non-random, unidirectional error that affects the accuracy of research results. This type of error consistently skews results in a specific direction rather than varying randomly, which makes it a significant threat to the internal validity of a study. When systematic errors occur, they can lead researchers to draw incorrect conclusions about the relationship between variables because the results may not accurately reflect reality. Unlike random errors, which can average out over time and trials, systematic errors persist throughout the measurement process and can compromise the integrity of the research findings if not addressed. Recognizing and mitigating bias is essential for ensuring valid and reliable research outcomes.