the second step, we examine whether the effect of government size differs depending on whether we are in an efficient or an inefficient year.
Consider the first step. When Δgovqual is positive, which implies an improvement in the quality of public infrastructure relative to the previous year, we classify the government in that year as being “efficient”. Conversely, when Δgovqual is negative, we classify the government in that year as being “inefficient”. This simple classification rule implies that the Greek public sector is classified as “efficient” in 22 years and as “inefficient” in 17 years, over the period 1960-1999.20
6. 2 Estimation and tests
Given this classification, we move on to the second step by regressing growth on our principal measure of the overall size of government (namely, the growth rate of the share of government in GDP, Δgovshare) by allowing the size effect to differ between the efficient and the inefficient sub-sample (denoted respectively as Δgovshareeff and Δgovshareineff). The results, reported in column 2 of Table 4, reveal a non-linear relationship between fiscal spending and economic growth. As can be seen, Δgovshareineff is significantly negative at the 1% level, while Δgovshareff is quantitatively small (close to zero) and insignificant. The estimated quantitative effect of Δgovshare in the inefficient regime is important, as this is more than double than the average effect reported in Table 2. Note that these results are net of any direct effect of Δgovqual on growth, because we have controlled for Δgovqual in the regression (the latter is positive but not significant).
Notice that the effects of dummy variables are also affected relative to section 4 (compare new results with those in column 3 of Table 2). That is, the d(1960-1973) dummy is now insignificant although still positive, while the d(1980-1993) period remains negative and significant. It is interesting that the d(1994-2000) dummy now turns to be significantly negative. An obvious explanation is that all recent years have been classified as efficient, so that the positive effect on growth has been already controlled for (via the size-efficiency mix).
It is also important to note that the R2 in this model jumps to about 80%. This is a rather impressive fit. It implies that the growth in the share of government in GDP, when allowing for a non-linear Laffer curve-type effect, can explain - along with some simple political dummies - around 80% of the variation of the growth rate