4/RT/99 - Measuring Structural Budget Balances in a Fast Growing Economy: the Case of Ireland

The most popular method of measuring structural budget balances is the “gaps plus elasticities” approach. In this paper, it is argued that the idiosyncratic features of an economy need to be accounted for properly when seeking to achieve good estimates of structural budget balances using this method. The first step in this approach involves measuring the economy’s potential output in order to identify an output gap that indicates the economy’s cyclical position. There are two main approaches to measuring potential output a production function approach and a trend smoothing approach. The paper highlights how estimates of potential output growth can vary quite considerably between these two approaches in an economy such as Ireland due to the manner in which the high mobility of productive factors can impact on the production function approach and in how very high recent growth rates impact on the trend smoothing approach. The second step of the gap plus elasticities approach requires measuring the sensitivity of revenue and expenditure items to the output gap in the form of an elasticity. In the standard estimation procedure, these elasticities are generally assumed to remain constant over the cycle. Evidence from Ireland, however, suggests that an assumption of constant elasticity values is unlikely to be plausible in practice. On the contrary, cyclically-sensitive fiscal policy will introduce timevariance into elasticity measures. There may be a need, therefore, to assess and quantify the significance and consequences of time variance in elasticity measures and its implications for structural budget balance estimation.