Not all conversion rates are created equal. A 57% rate from 33 leads is not the same as 36% from 706. Ivan Baldin reflects on how to add confidence interval bounds to your sales conversion charts using standard deviation and Excel stock chart candlesticks.

Your conversion rate isn’t a fixed number — it’s a confidence interval. Using binomial distribution, this post shows why a 2% conversion rate on 200 leads could really be anywhere from 0.4% to 3.6%, and why setting sales targets on small samples is madness.

Your new sales rep is converting at 10% instead of the expected 16%. Fire him? Not so fast. Using the binomial distribution function built into Excel and Google Sheets, you can calculate the exact probability that poor results are just a cold streak — and make staffing decisions you can actually defend with math.