Can Japan resist the demographic decline? The role of policy delays and prior announcements

This paper quantifies the long-term effects of policy interventions designed to address Japan's rapid demographic decline. Using a dynamic lifecycle simulation model, we focus on two critical factors: implementation delays and the impact of prior public announcements . Our findings demonstrate that while countermeasures can effectively improve demographics and per-capita welfare, their positive impacts are highly sensitive to timing. Specifically, a policy delay dramatically reduces the long-run population and welfare gains. Conversely, we show that providing advance notice generates significant benefits, as even a one-year announcement allows for meaningful household behavioral adjustments. These results underscore the critical importance of both timely action and clear communication for effective population stabilization strategies.