This only helps much if the calibration is off linearly - in my case not only is the calibration off but the temperature flux up/down is more pronounced than it should be. I still make do, but it's definitely very easy for stuff to come out burnt or undercooked as a result.
Other have suggested ways to check your oven temp control, but one way to mitigate the problem slightly is to add some thermal mass to your oven. Unglazed quarry tile makes a nice baking surface and a double layer of that will prevent big temp oscillations in your oven.
When the temperature sensor in caked with something that provides thermal insulation the resulting lag in temperature feedback would mess with the oven's temperature control.
