lists the attribute problem incidence rate for each attribute in a column next to its gap score. (The percent of customers who experienced a problem with the service attribute within the past 30 days). It will be important to take into account the rate at which a problem with an attribute occurs within the customer base. It may be that a particular attribute has a large gap score (and thereby a significant impact on overall satisfaction), but the percent of customers reporting a problem with the attribute is relatively small. In this case, it probably is not worth a transit agency's time and expense to attempt to further lower the problem occurrence rate for the attribute. On the other hand, if an attribute's gap score (impact on overall satisfaction) is moderately low, while the rate at which customers experience a problem with the attribute is high, the effect of the attribute on overall satisfaction is magnified and will require attention. Whether future increases or decreases in problem incidence rates are statistically significant can be validated by statistical tests (e.g., chi-square test, z-test of proportions, etc.).