I need to track slippage on projects. I have a 'baseline' date and a 'latest forecast' date, so can easily identitfy that slippage has occured and when, using TODAY(). However, I need to record the date the slippage FIRST occurred - in other words, I only want to do the date comparison once. If I do an 'if the date slippage first occurred cell is blank do the comparison' I get a circular reference. I'd be grateful for any suggestion as to a workround.