How is an individuals control chart used? It plots averages of subgroups rather than individual measures to set control limits and then apply these to new data for the purpose of monitoring the process for out-of-control signals. It is used to collect 20 to 30 data points to set control limits and then apply these to new data for the purpose of monitoring the process for out-of-control signals. It consists of only one individual chart in order to monitor a process for out-of-control signals. It is used to plot averages of subgroups rather than individual measures to set control limits and then apply these to new data for the purpose of monitoring the process for out-of-control signals