Welcome to the topic of continuous quality improvement (CQI)! "CQI: Data" is a video course meant to show how data can be documented and analyzed for continuous quality improvement in your organization. This video lesson, "How Much Day Do You Need?", is the final in a series of five. From it, the viewer will learn how to determine the amount of data to collect for both qualitative and quantitative data sets. For quantitative data, this lesson also shows how to compute and use standard error to determine sample size.