Common source bias

Occurrence

Common source bias can be categorised into two types: common method bias, also known as common method variance, and common source bias. Common method bias occurs when the same method or instrument is used to collect data from multiple sources, which can lead to an over-representation of certain factors. Common source bias occurs when the information or data collected is influenced by a single source, such as a single individual, group, or organisation.

One of the major causes of common source bias is the influence of the source on the data collected. For example, if a survey is conducted by a single individual, their own beliefs, biases, and perspectives can influence the responses of the participants. This "self reporting" is subjective, and limited because it is based on attitudes, values, and behaviours of the individual.

Common source bias is also present in participant selection. If participants are selected based on their association with the source, then their responses may be biased towards the source’s perspective. If participants are selected based on their willingness to participate, then their responses may not be representative of the population as a whole.