The study looked at changes in the volatility of 215 US economic indicators from 1960 to 1996. They found that most of these indicators had a shift in volatility during this time. Real variables became less volatile since the early 1980s, leading to more stable output growth. On the other hand, nominal variables saw temporary increases in volatility around the same period. This suggests a trade-off between short-term volatility and long-term growth patterns in the US economy.