In conducting your brand strength survey, you’ll reach a point where you have row upon row and column upon column of data. You’ll make tables from subsets of your data to highlight, say, the relationship between education levels of survey respondents and their perception of your brand. But how do you spot the meaningful relationships among all the numbers?
Indexing is an easy way to identify and gauge important subgroups and outliers. An index is simply a ratio of percentages: the percentage of a survey subgroup on a measure compared to the percentage of the general survey population on the same measure. An index score of 1.00 means that the subgroup exactly matches the general population on that measure.
Here’s an example, using the relationship of education level and brand perception. Let’s suppose you’ve found the following information in your analysis:
- Across your entire survey, 63 percent of respondents viewed your brand favorably or very favorable.
- Among those with at least some college education, 71 percent viewed your brand favorably or very favorably.
- Among those who had completed a four-year college degree, 76 percent viewed your brand favorably or very favorably.
Expressed as an index, those with some college compared to all survey respondents is 71:63. If you divide 71 by 63, you get 1.127. You can then say that those with some college education are 12.7 percent more likely than the general population of the survey to view your brand favorably or very favorably.
The index of those with a four-year degree is 76:63, or 1.206. That means these degree holders are 20.6 percent more like to view your brand favorably.
Of course, indexes can be negative as well, when a subgroup scores lower than the general population.
How you assign significance to index scores can be subjective. You can determine that you’ll only investigate further those indexes that are, say, 15 percent above or below the norm.
In the case of our example, you’d then do further research on the respondents with a four-year college degree, to see what else you might glean about them as a group. You could do more in-depth analysis of their responses, conduct phone interviews with individuals, or hold focus groups.
Your goal would be to discover why this group has a higher-than-normal opinion of your brand, and how you might exploit that fact. You might decide to try attracting more college degree holders or replicating the salient conditions of college degree holders among other subgroups in your general audience.
Indexing gives you a comparative power that you don’t get with other simple statistics alone like minimum, maximum, average, percentage, and mode, and yet is easy to calculate and understand. Indexes can point the way to further discovers about your brand and your audience.