"The vast majority of commercial web data we analyse, even as professionals, is poor quality." A large part of my job involves auditing Google Analytics setups in order to establish the quality of the data collected. This story brings together some of the extraordinary findings of my work. Its a study of 75 enterprise websites using Google Analytics. The results are somewhat surprising (and depressing) in that they show the general poor quality of data that organisations are working with. For example: the Average Quality Index score is only 35.7 out of 100, and one in five websites have a PII issue i.e. were collecting personal information into Google Analytics.