Advertising Principles - Evidence-based principles


Finalist for AMA’s 2011 Best Book in Marketing


A complete description of the principles has
been published in Persuasive Advertising

German Edition available

Chinese Version available

Dictionary of terms used in Advertising Principles

There are 61 entries in this glossary.
Search for glossary terms (regular expression allowed)
Begins with Contains Exact term Sounds like
All A B C E F G H I J L M N R S T U V W
Term Definition
Focus group interview

A research method that brings together a small group of consumers to discuss a topic, such as a new product, under the guidance of a trained interviewer. Focus groups are often misused. They should seldom be used for research because they are biased, inefficient, and expensive. They were not designed to evaluate or to predict; but unfortunately, they are often used for these purposes. In short, do not use focus groups to evaluate advertising. Here are the reasons:

  1. Biases occur in selecting samples. Selection of focus group members often necessitates self-selection because it requires that a group meet at a specific time and place.

  2. Sample sizes are small. Because people interact with one another within the group, a researcher cannot claim that the observations of each member are individual.

  3. Responses are biased by other subjects. In scientific work, effort is devoted to ensuring that other subjects do not bias subjects’ responses. In focus groups, people listen to others and they are influenced by their responses.

  4. Biases occur because of the administration. Questions are often modified by the leader to favor a particular answer; such modifications might be unintentional. In addition, customer responses are subject to interpretation, creating another potential bias.

  5. People tend to treat the responses as good predictors. There is no evidence that focus groups provide useful predictions.

  6. Focus groups are expensive.


© Copyright J. Scott Armstrong and Kesten C. Green. All rights are reserved.

Contact us with any suggestions here