The study looked at whether countries with a lot of debt have trouble growing their economies. They found that having too much debt can slow down growth, but only up to a certain point. For countries with good policies, debt starts to hurt growth when it reaches 15-30% of their economy, but it stops mattering much when it goes above 70-80%. For countries with bad policies, the thresholds are lower. However, there is a chance that debt may not affect growth at all in some cases.