When should I recalculate a Formula PI?
It is advisable that you only recalculate a PI’s formula when all feeder PIs have values entered and activated for all the same time periods. This is because formula recalculation will replace all existing data.
If there is missing data in time periods across the feeder PIs, a calculation will not take place for those time periods on the Formula PI; any existing data will be replaced with a blank cell.
With a formula PI using a small number of feeders this may not cause too much of an issue. However, if you have a large and complicated formula, troubleshooting where data is missing can be very time-consuming.
What can I do instead of formula recalculation?
If you need to recalculate a specific time period in your Formula PI, and you know/are unsure that recalculating the formula will cause lost values; there is a safer alternative. Formulas only work with the latest activated data; i.e. on the values activated after the formula has been setup.
Therefore, you will need to emulate the input of the values against these time periods. In order to do this, these values will need to be deactivated for a feeder PI, and then reactivated. Pentana Risk recognises this as value entry, and the formula should calculate correspondingly.
What should I look out for before recalculating?
When recalculating formula data for a PI that is displaying an RAG status, all RAG statuses will update using the current gauge setup. This may cause incorrect status changes for historical time periods, as the gauge setup may have been different when the data was entered and activated.