This article was published in the June 2017 edition of Graphic News magazine, the publication of the Printing Industries of Michigan.

I have a background in mathematics and statistics, and have always appreciated a strong, data-driven analysis. Today, with the power of modern computing and the evolution of analytical techniques, data is our crystal ball. And this applies not only to hard questions of science, like curing cancer or how to make a recyclable rocket, this applies also to sales and marketing.

Way back in the Stone Age known of the late 90s while an undergraduate mathematics major, I conducted a study on traffic violations at key intersections across town. My home at the time sat on a busy intersection close to campus, and again and again I witnessed first hand as drivers ran stop signs, disregarded pedestrians, and drove with a carelessness that risked lives.

After some period of time, I was able to identify trends and to build profiles of drivers as they approached the intersection. “Oh here comes that kid in the red sports car, he’s going to run it” and by and large he would. “Here comes Mr. Suit-and-Tie, he’ll stop” and usually it seemed he would.

So I set out to use the power of science to prove my convictions as to who the worst drivers were and how bad the problem really was. I sampled 5,000 instances of vehicles approaching four way stop-sign intersections over the course of a semester and recorded whether they came to a complete stop. Moreover, I recorded all sorts of additional variables: type of vehicle, apparent age of the driver, apparent gender of the driver, decals and stickers, spoilers, tinted windows, car, truck, van, color of vehicle, etc., and set out to do my analysis, a 20-page scientific paper.

In the end, I was shocked. My pre-study observations, while not completely off, were essentially wrong. It turned out the worst driver of all is the male middle-aged driver of the white van or mini van, not the kid in the red sports car. And this by a long shot.

Herein lies the power of robust statistical analysis: when its methods are followed properly, it dispels bias (to a degree of confidence, of course) and helps you see the truth.

And the same goes when approaching the question of the effectiveness of sales and marketing technique.

A recent study by published by the Journal of Experimental Social Psychology examined not just the effectiveness of in-person communication versus email communication when trying to convince someone to do something (in this case to fill out a brief survey), the study also sought to examine the perceptions associated with the effectiveness of the technique used by the survey-givers.

Of course, they found that in person communication was more effective. In fact, they were able to quantify this to a statistically high degree of confidence. In-person communication is 34 times more effective than email communication. Other studies have already established this, and I’m sure this confirms everyone’s gut feeling that email is just a lower quality, less subtle form of communication and selling, like any art, requires subtlety.

But what was very surprising, and I think is a vitally important take away for business owners and managers, is that the study also asked the survey-givers how effective they expected their efforts to be, whether they were assigned to request 10 survey completions in person or to request 10 survey completions over email.

From a report in Harvard Business Review: “Participants in the face-to-face condition guessed that on average 5 out of 10 people would agree. Participants in the email condition guessed that on average 5.5 out of 10 people would agree. This difference was not statistically significant; participants who made requests over email felt essentially just as confident about the effectiveness of their requests as those who made their requests face-to-face, even though face-to-face requests were 34 times more effective than emailed ones.”

That is to say, people, in our world salespeople and marketers, are prone to vastly overestimate the effectiveness of email communication.

Remember this during your next sales or marketing campaign.

About the author: Charles Groce is the CEO of Pearl Street Consulting, a Michigan-based IT, web, and software consultancy.