The Dutch business cycle was studied by creating an indicator to track economic ups and downs. The researchers used a special filter to identify cycles lasting 3 to 11 years. They looked at industrial production, household spending, and job numbers to gauge economic health. A mix of financial data, surveys, and real activity indicators were used to predict future growth. The indicator was tested to see how well it predicted changes in the economy over time. Finally, the researchers used this indicator to forecast future GDP growth rates.