Information bias (epidemiology)

Information bias is when the information you collect about a group or subject isn't accurate. In epidemiology, it means if researchers study a group of people, or a group of data, and the information they use isn't true, then the results of their study may be wrong. For example, if a group of researchers wanted to study how many people in a town have allergies, but their survey only asked people who went to the doctor, the results of their study won't be an accurate reflection of the whole town because people who don't go to the doctor won't be in the survey.