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When it doubt, go with the bigger number.By Thomas R. Schori, Ph.D., and Michael L. Garee, Principals, Millennium Marketing Research, 808 E. Ironwood, Normal, IL 61761-5239. Over the years, weve seen reasonably intelligent businesspeople regularly make some rather ill-advised marketing decisions, as a result of their misunderstanding of simple statistics. Unfortunately, its not just those whose only exposure to statistics was in a college Economics 101 class or an industry seminar on beginning marketing research who make such decisions. Otherwise intelligent people, with varying degrees of education and expertise, also make these same, faulty decisions. Let us illustrate. Suppose a marketer has developed two different print advertisements for a product. Since only one ad will ultimately be run, the marketer wisely decides to test the two ads among consumers, and then pick the ad which "performs" best in the test. While there are a number of ways an ad test can be conducted, our marketer decides to do a "mall-intercept" test. Consumers, representative of the target market, are shown a collection of ads for numerous products within the same product category, including of course the marketers product. One-half of the consumers are shown ad "A," and the other one-half, ad "B." After being exposed to the ads, consumers are then asked a series of questions designed to determine which ads they best recall. In the best case scenario, the results may leave no room for ambiguity. For example, if ad "A" registered a recall score of, say, 80%, and ad "B" a recall score of, say, 40%, then obviously, the choice of which of the two ads to run would be crystal clear. Problems arise, however, when the results are quite so neat. Lets say, for example, that ad "A" had a recall score of 82%, while ad "B" had a recall score of 78%, and the difference between the two scores is shown to be not statistically significant. What to do? Oftentimes, otherwise bright professionals will conclude things such as the following:
While such conclusions may seem reasonable, actually, they arent appropriate here. That the difference was not statistically significant really only means that differences between the two recall scores could have occurred by chance more than 5% of the time, i.e., more than 5 times in 100 such tests (assuming the criterion for statistical significance was set at the .05 level). So, what would be a more practical conclusion to draw in this situation? Actually, its quite simple. Determine if there are any other criteria that should be considered before deciding upon which ad to run. For example. . .
If the answers to each of these questions is "no," then the most logical decision to make is simply to "go with the bigger number!" That is, run ad "A" which had an 82% recall score, rather than Ad "B" which had a 78%. It really isnt any more difficult than that! |