Hi All!

I would really appreciate your help regarding creating control charts in SPSS.

My problem is that the process I am supposed to measure, is, out of control.

In my case, the USL of the process is around 17 (days). But since the process is out of control, there are cases when it is over 17. 

Also, The goal of the process should be around 10 (days). Right now the Mean of the process is around 15 (days). 

So, right now, when I calculate a control chart with SPSS, I get higher Upper Control Line value than Upper Specification Limit.

(UCL value is around 22, while USL is 17). Which shows that the process is bad, but I think that the value of 22 makes no sense, since when it is over 17 it is already bad and needs change ASAP.

So, I would like a control chart where, if a measured data surpasses a specification limit, it would show as a "rule violation". It makes no sense that if it is higher than 17 but lower than 22 it would show up as a "good value", when it is not the case.

The values which are used are monthly values. (1 value each month). 

How would you set up the control chart so that it shows when USL has been violated?


Thanks!