The study looked at how quantitative easing affected the Japanese economy when interest rates were already very low. They used a new method to analyze the data and found that when the central bank used quantitative easing, it lowered long-term interest rates, boosted output and prices, but these effects were only temporary. This means that while quantitative easing helped the economy in the short term, it didn't lead to a lasting increase in inflation. These findings are important not just for Japan, but also for other countries facing similar challenges with low interest rates.