Clearly, then, the states gained from transition, while the Centre lost. But exactly how much were these gains and losses? Answering that question requires a framework, set out in the Table. We compare actual collections relative to two benchmarks: average revenues pre-GST; and the revenues if the pre-GST arrangements and associated buoyancy had remained in place during the GST transition period. Admittedly, making these comparisons involves some assumptions, but the results are reasonably robust (and described in our forthcoming paper).
Our framework suggests the Centre lost significant amounts of revenue because of the transitional arrangements, between 0.6 per cent and 1 per cent of GDP every year (depending on the comparison and assumptions) during the seven-year transition.