Bias in Government Forecasts

Why do so many countries so often wander far off the path of fiscal responsibility? Concern about budget deficits has become a burning political issue in the United States, has helped persuade the United Kingdom to enact stringent cuts despite a weak economy, and is the proximate cause of the Greek sovereign-debt crisis, which has grown to engulf the entire eurozone. Indeed, among industrialized countries, hardly a one is immune from fiscal woes.

Clearly, part of the blame lies with voters who don’t want to hear that budget discipline means cutting programs that matter to them, and with politicians who tell voters only what they want to hear. But another factor has attracted insufficient notice: systematically over-optimistic official forecasts.

Such forecasts underlie governments’ failure to take advantage of boom periods to strengthen their finances, including running budget surpluses. During the expansion of 2001-2007, for example, the US government made optimistic budget forecasts at each stage. These forecasts supported enacting big long-term tax cuts and accelerating growth in spending (both military and domestic). European countries behaved similarly, running up ever-higher debts. Predictably, when global recession hit in 2008, most countries had little or no “fiscal space” to implement countercyclical policy.

In most cases, the problems have long been plain for objective observers to see, but public officials kept their heads buried in the sand. Over the period 1986-2009, the bias in official U.S. deficit forecasts averaged 0.4 % of GDP at the one-year horizon, 1% at two years, and 3.1% at three years. Forecasting errors were particularly damaging during the past decade. The U.S. government in 2001-03, for example, was able to enact large tax cuts and accelerated spending measures by forecasting that budget surpluses would remain strong. The Office of Management and Budget long turned out optimistic budget forecasts, no matter how many times it was proven wrong. For eight years, it never stopped forecasting that the budget would return to surplus by 2011, even though virtually every independent forecast showed that deficits would continue into the new decade unabated.