Pronab Sen, former chief statistician of India, said the two indicators are used for different purposes, depending upon the macro condition one is trying to address.
“When you focus on the debt-GDP ratio, you are trying to hold down the level of interest that comes in every year's budget. The fiscal deficit becomes important because it is government borrowing. It's a flow, not a stock. When you're looking at flows, the important thing about the fiscal deficit is whether it is crowding in or crowding out private investment. In the current situation, where private investment is doing nothing, a high fiscal deficit is actually a good thing. As private investment starts picking up, you should start reducing the fiscal deficit to make space,” he added.