If strategy is the blueprint for consumer personalization execution, then data is the fuel. Yet data is a top challenge discussed in personalization programs. Companies grapple with a myriad of data challenges including missing data, siloed data, and nonactionable data. Four types of consumer data shape personalization efforts: zero-, first-, second-, and third-party data. And whether that data is static or dynamic matters, too. This report provides a guide to consumer data and gives companies a data checklist for personalization efforts.