Real-time estimation of the output gap in Japan and its usefulness for inflation forecasting and policymaking

This paper examines the methods used by the Bank of Japan (BOJ) for estimation of the output gap. Great emphasis is put on the real-time estimation problems. After reviewing the evolution of output-gap estimation at the Bank, I discuss advantages and disadvantages of the various output-gap measures. First, I examine the usefulness of the output gap for inflation forecasting and show that the real-time output gap sometimes includes too much noise. Second, I investigate the implications of the real-time estimation problems for policy evaluation. Third, I exploit the TANKAN to enhance the usefulness of the real-time output gap.