The study looked at how changes in different factors affect a company's profits over time. They found that changes in the amount of products made have a bigger impact on profits than changes in prices, labor costs, or productivity. The study also showed that industry growth plays a big role in this. Other factors like industry concentration and barriers to entry, as well as price and cost stickiness, also affect how profits change. This means that when a company's revenue changes a lot from year to year, it's likely because they made more or fewer products, not because prices changed.