Maintaining the compliance of spreadsheets.

Once you have completed validation of your spreadsheets, then comes the hard part - maintaining the system in a validated state.

So often we see large amounts of money spent on validating computer systems only to find that weeks after the project finishes, changes to the system and practices around the system effectively make the validation redundant due to poor control and maintenance of the validated state.

Change control of validated spreadsheets is crucial, as is having appropriate SOPs in place to ensure effective use and maintenance of the spreadsheets.

To get an overview of what ABB recommends to maintain compliance see the Maintaining Compliance presentation, available from here.

The conclusion

You MUST keep your validated spreadsheets in a validated state, or the whole of your effort is wasted. You need an efficient change control process coupled with SOPs and trained operators. Don't fail at this stage, you have worked too hard to get here.