Process Control Statistics can be considered a 'snapshot' of process statistics (mean, standard deviation, etc...) during a specified span of time. Process control statistics are created when control limits are calculated and snapshot relevant statistical values of the data that is used to create the control limits. Each different type of control limit will have its own set of process control statistics.
When there is a process change, a new process baseline can be created. When a new process baseline is created, control limits and process control statistics can be calculated for it. Process control statistics are stored in the database. The new process control statistics can be applied to those samples which have sample effective dates occurring during the process.
Process control statistics are only available when the Ford Stat rules are in effect. If the Ford Stat rules are not turned on, the process control statistics will not be available in the Process Control editor. However, the ability to create process baselines and manage changes to engineering data values is available.
When creating DataSets which will be used in a DataStack, keep in mind that if your processes do not match in all of the DataSets, the integrity of the data will be compromised and you will encounter problems with DataStack construction.