A new test was developed to check if certain economic data from Italy are related in a stable way. The test uses a special kind of math to see if the numbers in the data are connected in a consistent manner. This test can show if there is a change in the relationship over time or if it stays the same. The results of the test were compared with other tests to see if they all agree. The study also looked at real-life examples and ran computer simulations to confirm the findings.