The first, referred to as a univariate control chart, is a graphical display (chart) of one quality characteristic. The second, referred to as a multivariate control chart, is a graphical display of a statistic that summarizes or represents more than one quality characteristic. Characteristics of control charts Chart details. A control chart consists of: Points representing a statistic (e.g., a mean, range, proportion) of measurements of a quality characteristic in samples taken from the process at different times (i.e., the data) The mean of this statistic using all the samples is calculated (e.g., the mean of the means, mean of the ranges,