Industrial production is highly variable and connected across different sectors. Researchers used factor analytic methods to understand how much of this variability is due to common shocks affecting multiple sectors. They found that about 80% of the variability in industrial production is due to these common shocks, both before and after a period called the great moderation. These common shocks were more important in causing variations in individual sector output before the great moderation. Additionally, 5-15% of the variability in industrial production is due to sector-specific shocks spreading through input-output linkages.