In the fall of 2008 the U S stock market plummeted several times with grave consequences for the world economy

Question

In the fall of 2008, the U.S. stock market plummeted several times, with grave consequences for the world economy.

A researcher might assess the economic effect this situation had by seeing how much money people saved in 2009. That amount could be compared to the amount people saved in more economically stable years. How might you operationalize the economic implications at a national level?

Statistics and Probability