Common errors with control charts
Incorrect Data Ordering
Symptoms
Data selected for the control charts are clearly in wrong order. Typically data are sorted ascending or desceding order by the value, as is clear from run chart pattern. Image below show typical situation.
Incorrect data ordering in ImR-chart. Note x-axis values which show incorrect ordering. Note also the values are in descending order.
How to fix
The incorrect behavior is usually caused when trying to reuse a visual. Reusing a visual means that the source data is changed to different table. Behavior is fixed by deleting the control chart from the report page and adding it again.
Limits are way too narrow
See the ‘Ordering’.