Which of the following is NOT a field research technique?

Field research techniques are methods used to collect data directly from respondents in their natural environment, allowing researchers to gather qualitative and quantitative information relevant to their studies. These techniques typically involve direct interaction with participants, which helps capture immediate and authentic feedback.

Product testing, while it may involve observing participants using a product in a real-world setting, is more commonly categorized under experimental or laboratory research. It often focuses on assessing specific product attributes or performance rather than exploring broader attitudes or behaviors in a natural context.

On the other hand, personal interviews, customer audits, and postal surveys are all classic field research techniques. Personal interviews involve direct interaction with participants, allowing for in-depth responses. Customer audits gather data through direct observation or interaction, providing insights into customer behavior and experiences. Postal surveys facilitate feedback from participants via mailed questionnaires, making it a method for reaching respondents outside a controlled environment.

Consequently, product testing stands apart as it does not align with the traditional definition of field research techniques that are primarily focused on gathering data through participant interaction in their usual settings.