They are based on Canadian cost data, but that data is converted to U.S. dollars during the annual update process using the exchange rate at that time.
How this works
Area modifiers are calculated as differences from the U.S. national average, and the costbook is published in U.S. dollars. Because of that, the modifiers are also published as U.S.-dollar adjustments.
What you’ll see in your estimate
When you apply a Canadian area modifier, it adjusts the published figures and produces an estimate in U.S. dollars.
If you need Canadian dollars
If you want your estimate in Canadian dollars, apply a currency exchange rate after using the area modifier.