The article looks at whether temporary factors play a big role in stock price changes. They use variance ratio tests to analyze stock returns in the US and other countries. The results show that stock prices tend to go back to their average in the short term, but move away from it in the long term. This suggests that temporary factors make up a significant portion of stock price changes. The researchers suggest that these temporary changes could be due to shifts in required returns or temporary trends in stock prices that last for a few years.