Sampling bias is an error related to selecting the survey respondents. It happens when a survey sample is not completely random.

If certain types of survey takers are more or less likely to participate in your research, you might be introducing sample selection bias into your research. For example, creating an online poll with the question "Do you have internet access?" will lead to almost 100% of participants answering "Yes."

To avoid sampling bias, make sure your survey is distributed in a way that all types of respondents get a chance to respond to it. This might mean using several distribution channels and collection methods. Look for ways to encourage diversity in the sample by asking yourself, “Who haven’t we talked to yet?” Also, be careful of the conclusions drawn from any one study.^[1]