This is not process control in the sense of feedback control theory. It refers to using statistics to monitor industrial processes. When people like Deming started promoting industrial quality control, it was their intention to provide very simple tools that any factory worker could use to monitor and improve processes on their own or in small groups. So they favored graphical analysis over sophisticated statistical tests. A basic control chart was easy for anybody to produce.
https://asq.org/quality-resources/control-chart
This is not process control in the sense of feedback control theory. It refers to using statistics to monitor industrial processes. When people like Deming started promoting industrial quality control, it was their intention to provide very simple tools that any factory worker could use to monitor and improve processes on their own or in small groups. So they favored graphical analysis over sophisticated statistical tests. A basic control chart was easy for anybody to produce.