Research Instruments include mechanical or electronic devices, although the survey questionnaire is the most common instrument for marketing research. Observations of actual behavior may not help understand why people act as they do. Ideally, you're a fly on the wall in the mind of your customer while he or she decides to buy. It's not ideal, but you an learn a lot from watching people use a web site. Keith Instone 's Usable Web site has a couple dozen links to user testing information that will get you started.
Experiments establish cause and effect relationships.
However, controlling for variables such as the 4 P's is difficult in real-world situations. We're reluctant to experiment on people. They help people describe reasons for their behavior, but surveys can be plagued by problems in completion. They presume self-knowledge and a willingness to reveal it. Mail questionnaires They provide excellent control over interviewer effects.