É o assunto em destaque nos capítulos analíticos do World Economic Outlook. Vale a pena ir analisar. Mas o FMI devia ter mais cuidado: isto é o tipo de coisa fácil ser lido em diagonal e citado às três pancadas.
As for the macroeconomic impact of increased public investment, the chapter finds that such investment raises output in both the short and long term. It also finds that these effects vary with a number of mediating factors, and these are fundamental to teasing out the chapter’s policy implications (…)
For economies with clearly identified infrastructure needs and efficient public investment processes and where there is economic slack and monetary accommodation, there is a strong case for increasing public infrastructure investment (…) The increased public investment would provide a much needed boost to demand in the short term and would also help raise potential output in the long term.
These conclusions should not, however, be interpreted as a blanket recommendation for a debt-financed public investment increase across all economies. Adverse market reactions—which could occur in some countries with already-high debt-to-GDP ratios or where returns to infrastructure investment are uncertain—could raise financing costs and further increase debt pressure.
But if infrastructure needs are indeed pressing and investment may be self-financing for some economies—in the sense that the public-debt-to-GDP ratio may not rise as a result of investment—why is public investment in advanced economies at a three-decade low? The reason is that in practice, public investment decisions frequently are not guided by economic rationale. This can cut both ways—inefficient and unproductive projects are often pursued by politicians and line ministries when they should not be, and some productive projects (and importantly, maintenance) are forgone when they should be given priority. Regarding the latter, Box 3.5 illustrates how improvements in fiscal institutions and some fiscal rules seem to help preserve public investment during periods of fiscal consolidation
Increasing investment efficiency is critical to mitigating the possible trade-off between higher output and higher public debt. Thus a key priority in many economies, particularly in those with relatively low efficiency of public investment, should be to raise the quality of infrastructure investment by improving the public investment process. Improvement could involve, among other reforms, better project appraisal and selection that identifies and targets infrastructure bottlenecks, including through centralized independent reviews, rigorous cost-benefit analysis, risk costing, and zero-based budgeting principles