Both variance types are crucial when trying to stay within the scope of the project. Schedule variance is calculated by subtracting the planned value out from the earned value (EV-PV). Schedule variance gives the PM an idea of where they are at in the project; which is necessary because it will allow them to know whether the project needs to be sped up or remain at its current progress. Cost variance is found by subtracting the actual cost from the earned value (EV-AC). As previously mentioned, cost variance tells where the project is at in terms of budget consumption. I would not compare these two and say one is more important than the other because both are equally required. A PM most certainly needs to know how much is left in the budget, but they also need to know how much longer the project will take to complete in order to properly plan how much more of the budget can be consumed, or if they need to acquire more money. Both are interdependent in a way, and allow for a much broader view of what’s to come in terms of project requirements. The way I see you really shouldn’t have one without the other.