We define observational research as any research that can be carried out without asking questions, and which consists of the recording of factual events. Peoples' behaviour can be monitored in this way; for example, by recording numbers entering stores at particular times of day or year, or by watching peoples' eye movements to see which products draw their attention. Observational research can also be used to record data such as traffic volume in order to create a model for areas of congestion.

Compared with the other methods, observational research offers the major advantage that the information is objective and does not depend on respondent co-operation. It removes from consideration, therefore, all the usual concerns about the effect the research process itself has on the information obtained.

One specific type of observational research is PCP's Residential Property Monitor which uses a representative route through a town to build an accurate picture of the housing market. However, these procedures could also be used to carry out all kinds of city and town level research, including differences in provision of council services, and maintenance of houses or gardens.