The study looked at how real wages and economic activity are related during different phases of business cycles. They used a method to separate short-term and long-term cycles and found that the correlation between real wages and economic activity has weakened since 1980. Real wages tend to move with short-term cycles but against long-term cycles. Before 1980, real wages were more flexible downwards and rigid upwards, but after 1980, they became more flexible upwards and rigid downwards. Supply-driven economic cycles are more likely to lead to real wages moving in the opposite direction before 1980, but the opposite is true after 1980.