ill in our index for large groups of people, we need to institute an approach that allows us to extrapolate the results of a small number of surveys across larger populations. We can do this through the miracle of statistical analysis and extrapolation. The subject of extrapolation and statistical sampling is a large and complex one, and many books have been dedicated to the subject. In order to load our CCI with survey data, we must either survey the entire population in question (segment or group), or employ sampling techniques. It is not at all unreasonable, for example, to do a 100 percent survey for the top 10 percent of your customer base, or for your top two segmentation groups. eXcellence in Telecommunications The Telco Churn Handbook On the other hand, strategic use of surveys within the context of a sampling approach can yield valid numbers for many groups and for the entire customer population. Derivation of Values Based on Available Data The other way we can collect the values for our CCI is to look at the available data in our systems and derive the values. For example, a check of call detail records can show us which customers are having more dropped calls. We can use this data, the number of dropped calls, to derive a customer ranking for call quality. Similarly, an audit of customer service complaints can provide us with a customer value for customer service appraisal. Commercial and Consumer Derivations One particularly useful and easy-to-apply set of derivations is to make a distinction and some assumptions about the differences between consumer and commercial users. For example, we might be able to assume that commercial customers care less about image and more about price. Assumptions Based on Psychographics and Demographic Segments The other technique that has proven fruitful in the past has been to create behavioral, psychographics, and demographic profiles of groups of customers and then derive or assign the most likely values for each factor based on an understanding about the segments and