This paper investigates how macroeconomic uncertainty affects the fiscal multiplier of public investment. In theory, uncertainty can reduce the multiplier if the private sector becomes more cautious and does not respond to the fiscal stimulus. Conversely, it can increase the fiscal multiplier if public investment shocks improve private agents’ expectations about future economic outlook, and lead to larger private spending. Using the disagreement about GDP forecasts as a proxy for uncertainty, we find that unexpected increases in public investment have larger and longer-lasting effects on output, investment, and employment during periods of high uncertainty, with multipliers above 2, and the larger multipliers are not driven by economic slack. Public investment shocks are also found to boost private sector confidence during heightened uncertainty, driving-up expectations about future economic development which in turn magnify private sector response to the initial stimulus.

This paper provides new evidence of the macroeconomic effects of public investment in advanced economies. Using public investment forecast errors to identify the causal effect of government investment in a sample of 17 OECD economies since 1985 and model simulations, the paper finds that increased public investment raises output, both in the short term and in the long term, crowds in private investment, and reduces unemployment. Several factors shape the macroeconomic effects of public investment. When there is economic slack and monetary accommodation, demand effects are stronger, and the public-debt-to-GDP ratio may actually decline. Public investment is also more effective in boosting output in countries with higher public investment efficiency and when it is financed by issuing debt.

We contribute to the intense debate on the real effects of fiscal stimuli by showing that the impact of government expenditure shocks depends crucially on key country characteristics, such as the level of development, exchange rate regime, openness to trade, and public indebtedness. Based on a novel quarterly dataset of government expenditure in 44 countries, we find that (i) the output effect of an increase in government consumption is larger in industrial than in developing countries, (ii) the fisscal multiplier is relatively large in economies operating under predetermined exchange rate but zero in economies operating under flexible exchange rates; (iii) fiscal multipliers in open economies are lower than in closed economies and (iv) fiscal multipliers in high-debt countries are also zero.

This paper reviews the theoretical and empirical literature on the effectiveness of fiscal policy. The focus is on the size of fiscal multipliers, and on the possibility that multipliers can turn negative (i.e., that fiscal contractions can be expansionary). The paper concludes that fiscal multipliers are overwhelmingly positive but small. However, there is some evidence of negative fiscal multipliers.

The world economy is experiencing a very strong but uneven recovery, with many emerging market and developing economies facing obstacles to vaccination. The global outlook remains uncertain, with major risks around the path of the pandemic and the possibility of financial stress amid large debt loads. Policy makers face a difficult balancing act as they seek to nurture the recovery while safeguarding price stability and fiscal sustainability. A comprehensive set of policies will be required to promote a strong recovery that mitigates inequality and enhances environmental sustainability, ultimately putting economies on a path of green, resilient, and inclusive development. Prominent among the necessary policies are efforts to lower trade costs so that trade can once again become a robust engine of growth. This year marks the 30th anniversary of the Global Economic Prospects. The Global Economic Prospects is a World Bank Group Flagship Report that examines global economic developments and prospects, with a special focus on emerging market and developing economies, on a semiannual basis (in January and June). Each edition includes analytical pieces on topical policy challenges faced by these economies.

The global economy has experienced four waves of rapid debt accumulation over the past 50 years. The first three debt waves ended with financial crises in many emerging market and developing economies. During the current wave, which started in 2010, the increase in debt in these economies has already been larger, faster, and broader-based than in the previous three waves. Current low interest rates mitigate some of the risks associated with high debt. However, emerging market and developing economies are also confronted by weak growth prospects, mounting vulnerabilities, and elevated global risks. A menu of policy options is available to reduce the likelihood that the current debt wave will end in crisis and, if crises do take place, will alleviate their impact.

This issue includes a general assessment, a special chapter on the effects of digitalisation on productivity and a chapter summarising developments and providing projections for each individual country.