Welcome to the topic of continuous quality improvement (CQI)! CQI: Charts is a video course that describes a variety of charts that are useful for measuring and analyzing performance to continuously improve quality. This video lesson, Understanding Correlation, is the third of eight. This lesson defines correlation and explains what correlation means in the context of data. Viewers will also learn about confidence, the correlation coefficient, and the P value, as well as the 3-5-7 rule of thumb.