> Use actual statistics — Do not rely on simple 1 on 1 comparison metrics to dictate what works and does not work. “Version A yields a 20 percent conversion rate and Version B yields a 22 percent conversion rate, therefore we should switch to Version B!” Please do not do this. Use actual confidence intervals, z-scores, and statistically significant data.<p>This is my key takeaway from the article. So often the desired outcome is to move a needle without being specific about what a degree of movement means.