In economic indicator parlance, a "leading indicator" changes BEFORE the overall economy changes. (Think of the "lead dog" rather than the "leading lady".) A lagging indicator changes AFTER the overall economy.
The Business Roundtable quarterly surveys its corporate CEO members in a widely followed index. My friend Eric Fruits has dissected the data on the CEO Economic Outlook Survey and concludes that it's a lagging indicator. After a good quarter, CEOs say things are looking better. Not before, but after.