Correction Dose Negative Number

I don't know - but it looks confusing!
My Tandem pump will use such values in a bolus calculation but it's displayed as insulin on board.
Or perhaps I'm misunderstanding what it means on the Insight?

My pump also shows it better, it shows what you'd need to correct the BG to the value that I've set as my target value, then how much insulin is still active, and then shows the correction value minus the active value to get the total - shows zero if you have more insulin on board than the dose needed for the correction.
The instructions for the Insight may show you exactly which number means what.

But yeah it is just a minus number because you still have some insulin on board and that's how much its reckons is left (this will depend on the time you had your last bolus and what is set as the timer for said insulin - mostly its gets set to 4hrs as far as I can tell). Do you understand about bolus insulin lasting for about 4hrs (for most, but not all)?

On my Omnipod it means I have more insulin on board than I need. As I can’t take insulin away I eat some fast acting carbs to compensate. I calculate 12 g carbs per 1 unit of insulin. So if my Bolus calculator says -1.5 iu I take 18 g of glucose or 200ml of Orange Juice.

Another technique I sometimes use is to reduce the basal dose temporarily. So in the example above, if my basal was 0.5 iu per hour I could reduce it by 100% for 3 hours.