Three months later, the evidence was in. By axing the promotions, CVS sold fewer products at higher prices [yes, demand curves do slope downwards!]. Across the 400 stores that ran the experiment, profits were up. Not surprisingly, CVS soon put the change in place across all its 9000 stores. A simple randomized trial likely increased the organizations annual profit by $50 million.
On Gary Loveman, an economist who left Harvard to run Harrah's, and who comes to Vanderbilt to speak, said three are three cardinal sins at Harrah's:
...you don't harass women, you don't steal and you've got to get a control group.