For any given data point in a data set, there are primary factors that determine it’s worth. The primary factor is whether a data point is relevant to your market.
If you are selling wine, for example, the first factor is whether they are wine enthusiasts or not. This factor has a range of meaningfulness that is based on source. A member of a mail-order wine club is strong: so is a long-term paid subscriber to a Wine Enthusiast type magazine. This is considered ‘transactional’ data and carries more weight than any other source. A