Scientific Web Site Conversion Enhancement

I heard a client say recently that trying to make changes to an established site to increase its conversion rate was just haphazardly guessing, and they were corrected by someone who said that the right way to do it would be to guess and then test with multivariate tests. I disagree.
The scientific method says we should study the subject first, then make a hypothesis and test it. Study the site visitor’s current behaviors first through analytics or user testing/surveys. Then you can begin to make assertions about what problems said site visitors are having on the site and you can make the necessary conversion enhancements and test them.
Email me if you want to talk about boosting your conversion rates.
PS this site’s 1 year birthday was 2 days ago.