> The result was an extra 2 million orders a year. Does the author actually believe that the change of the form setup was solely responsible for the increase

> The result was an extra 2 million orders a year. Does the author actually believe that the change of the form setup was solely responsible for the increase in orders? Or was this just a poor choice of words? It is a pity that they didn't study (or publish) the results of an A/B test on this change.