To date, there is a complete lack of a standard methodology for measuring and quantifying eye data quality. We argue that the lack of standard measures makes several aspects of manufacturing and using eye-trackers, as well as researching eye movements and vision, more difficult than necessary. The terminology across different research fields and eye-tracker manufacturers varies and---although certain data quality terms are used widely in the literature---it is often difficult for the user to know what exactly these terms refer to. The eye-tracking community would benefit from a standardized methodology that offers clear and transparent definitions of the central terms. This is the purpose of the COGAIN technical committee for the standardisation of eye data quality measures. In our talk, we illustrate why data quality matters with examples, and review previous work on how it has been measured and reported, and finally describe how the standardization committe plan to carry out its work.