a concrete example, suppose you redesign your company website and that sales subsequently increase. That might lead you to believe that the redesign of the website caused the boost in sales. After all, one preceded the other. But how can you be sure? Perhaps sales went up not because of the new website, but because a rival went bust, or interest rates went down, or because it was a rainy month and more people shopped online. Indeed, it is entirely possible that sales would have gone up even more if you had not changed the website. Looking at the sales statistics is not going to help you find
...more
