Bias in market research?

Could someone briefly explain some factors that might cause bias in a sample of customers?

Bias in market research?
The idea of market research is to query a sample of the market to help formulate or validate assumptions about the entire group. This is an imperfect science and there are many factors that can bias the results of market research. Here are four of the most common ones.





1. Poor selection criteria. The criteria you use to decide who would be included in and excluded from your sample group. If you get this wrong then data from that sample wil not be applicalbe to the larger target group. E.G. You recruit people who are experts on your product are but your target has little specialized knowledge. As a rule you usually want to exclude people who work in or have strong attitudes about marketing and advertising (unless, of course, marketing types are your target).





2. Non-random selection. Bias can creep in when your survey population is drawn from one particular segment of the population particularly if that segment is not representative of your target. E.G. You recruit subjects through a blog yet only 2% of your target read blogs.





3. Study Design. Whether it is a web survey, in-depth interview, focus group, eye-tracking study etc... the way you ask the questions or pose the problem in itself will introduce a bias. E.G. Sometimes a survey question is asked in a way that suggests a certain answer, sometimes one member of a focus group may influence the answers of the others.





4. Analysis. One of the last hurdles and perhaps the most daunting is who interprets the raw data to draw conclusions from it. If the person analyzing the data has a vested interest in the results there is a strong chance the conclusions will be biased. To avoid this use someone who is more objective - but be sure they understand your business. I have seen objective outsiders completely misinterpret answers because they were not familiar enough with what was being discussed. This is particularly true when researching a specialist target group (as opposed to general consumers).