Intent to Purchase Rating

December 9, 2004 - by Robert E. Stevens, GENESIS II (The Second Beginning) E-Mail: views@aol.com

One of the Views readers called to ask if I had a historical file for Definitely Would Buy ratings. I told him I did and I would share them with him, but I would recommend any usage of the data be done with extreme caution.

It has been my experience that the rating scale results depend more on the protocol than the differences between concepts. My research has found that:

"Definitely Would Buy" results will differ by 20%, depending on where the data are collected (CLT vs. Mail vs. Telephone vs. In-store)
"Definitely Would Buy" results will differ by 20% between data collected via questionnaire (self-administered) vs. Interviewer administered (respondent does not see the questionnaire).
The use of the standard contingency question can add or reduce the DWB scores by 20%
Results will vary greatly depending on the category. For instance, laxatives will average 16% DWB with a range of 9% - 21% while Cake Mixes average 41% DWB with a range of 17% - 54%.
Results from well over 1,000 studies, across 21 product categories, show that no category falls below 9% DWB.

Two separate "Researching Research" projects that I reported on in an early 1990s Views showed the variations in results you can obtain with slight changes in protocols. In the first study, six concepts were tested using questionnaires both with and without the Definitely Would Buy contingency question. When the contingency question was present, the average DWB score for the six concepts was 35%. When it was not present, the average score was 15%. In the second study, we compared results collected in a Central Location Study with results obtained In-Store. three concepts were evaluated through interviewer administered questioning. The Central Location part of the study resulted in an average DWB score of 45% while the In-Store results showed a DWB score of 23%.

CAUTION: Never use a company's historical data base if they cannot tell you that the protocol used in the research was the same across the entire data base. Demand that data used to make judgments about the results of your test are from studies that used the same protocol and from the same product category. Better yet, include in your study a current product concept or some company standard concept. It may cost a little more but in the end, you will find it to be well worth the investment.

Know the source of your data. Know the when, where & how your data were collected.

Sponsor: Sorensen Associates Inc Portland, OR: 800.542.0123 Minneapolis, MN: 888.616.0123
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