 In research, bias refers to any systematic error or deviation from the truth that occurs during the data collection, analysis, or interpretation processes. Biases can occur due to many factors, such as the sampling methods, the researcher's subjective judgment or preconceptions, the study design, or the data analysis techniques used. There are several types of biases that can occur in research. Some of the most common types include selection bias. This occurs when the selection of study participants is not random and is influenced by some factor that is related to the outcome being studied. For example, if a study only includes participants who are willing to participate, this may bias the results. Measurement bias, this occurs when the measurement of the outcome or exposure is not accurate or consistent. For example, if a scale used to measure weight is not calibrated correctly, this could lead to inaccurate results. Recall bias, this occurs when participants in a study do not accurately recall information about past events or exposures. For example, if a study asks participants to recall their dietary intake over the past year, their responses may be influenced by their current dietary habits or biases. Reporting bias, this occurs when participants in a study do not accurately report information about their experiences or exposures. For example, if participants in a study are asked about their drug use, they may under-report their use due to fear of judgment or legal consequences. Observer bias, this occurs when the researchers' beliefs or expectations influence their interpretation of the results. For example, if a researcher believes that a particular treatment is effective, they may unconsciously interpret the results in a way that supports their belief. Sampling bias, this occurs when the sample of participants studied is not representative of the population being studied. For example, if a study only includes participants from a certain age group, this may not accurately represent the experiences of the broader population. Publication bias, this occurs when research that produces statistically significant results is more likely to be published than research that produces non-significant results. This can create an inaccurate representation of the overall body of research on a particular topic. It is important for researchers to be aware of and minimize biases in their work in order to ensure that their results are accurate, reliable, and valid.