Treasury and Finance said in the PEFO that Australia's terms of trade are going to fall by 5.75% this financial year. Iron ore, coal and oil and gas made up 50% of merchandise exports in 2012/13. Gold and base metals made up another 14%. A view about the prices of only a handful of commodities is critical to a terms of trade forecast. How bullish are the bureaucrats about iron ore prices or gold? Why don't the Commonwealth Treasury and Finance departments tell us their individual price assumptions so we can better understand the risks to the fiscal outlook? The answer is probably simple: Treasury knows the art of forecasting involves skilful use of countervailing errors. Bunch all the prices together in a way that is not entirely obvious and we will never know why they were wrong.