Why are warnings not showing up in Control Chart?

[#1]

Hi All,

Thanks in advance for helping with what is probably a simple issue!

One of my colleagues is trying to build control charts to track step yields at various unit operations for different drug product lots.  We have 7 lots thus far (A-G) and he'd like to use the first 6 to establish the control limits.  I built the control chart with the lots separated into two phases (A-F and G) and selected a few Warnings to try to display where we're out of limits.  However, no warnings are flagged.

The attached data table has the information and a script for the control chart.  Unit Op 1 is the key one in question: lot G should be flagged for Test 1 (outside 3s) but no warning is displayed. (Note:  I can force the label if I input Control Limits based on the UCL and LCL using the Phase 1 lots).

1) Is there something that I'm missing with the settings or general approach here?  I am not 100% sure that the control chart is the right tool for what he's trying to look at (i.e., whether lot G is non-conforming).  

2) If a control chart IS appropriate, why is lot G not getting flagged for Warning 1 (too few data points?  should we not be separating into phases, etc.)?

I've done a little searching but can't find any similar posts...apologies in advance if this has been addressed elsewhere.

Thanks again!

Chris  

[#2 · Accepted solution]

https://www.jmp.com/support/help/en/18.0/index.shtml#page/jmp/control-chart-builder-interactive-work...

Start by reading through Quality and Process Methods > Control Chart Builder > Additional Examples of Control Chart Builder ... .

View more...

Exclude G lot from your data

run control chart for your columns and save limits to column

remove exclusion from lot G and rerun control chart. This way it should still be utilizing the same control limits without G lot affecting them

There are other ways to get/save/load the control limits and you might want to explore those

[#3]

Hi Jarmo,

Thanks for the directions!  This is definitely a more streamlined way to achieve what I was doing before.  I suppose the original issue was that the 3SD limits from the Phase 1 lots weren't applied by default to the Phase 2 lot.

I appreciate your help!

Chris

[#4]

JMP's use of "Phase" differs from your valid idea of Phase 1 and Phase 2 in building a control chart. JMP uses this term to refer to any grouping such that each group has its own limits. For example, you might have a 'before' and an 'after' phases if you want to demonstrate better control.

In your case, exclude the last batch, build the chart, and save the limits to the data column. This establishes the limits from phase 1. Unexclude the last batch; it should not appear in its own phase or determine the limits. Additional batches likewise will be added to the chart but not update the limits.

A word of caution: 5 batches is a very small representation of the process to establish phase 1 limits.