Give Odds Estimates from Both Directions

You’re deciding whether to undergo a complicated medical procedure. The physician tells you there’s a 70% probability the procedure will help your condition. How would your trust in that estimate compare to the trust if you’d been told there is a 30% probability the procedure will not result in an improvement?
     The two estimates are logically equivalent, but researchers at Virginia Tech and University of South Carolina say you’d trust the first estimate more than the second and that you’d consider a physician who gave you the 70% estimate as having done a more thorough analysis than one who gives you the 30% estimate.
     Other studies find you would understand the 70% estimate better, since our brains have trouble with the word “not.” Researchers at University of Colorado-Boulder, Northwestern University, and INSEAD discovered that a toothpaste dispenser described as “not easy to use” received higher ratings than one described as “not difficult to use.” And we might like the 70% estimate better because it’s positive. Researchers at Seattle University and University of San Diego point out how consumers prefer a cut of beef described as 75% lean to one described as 25% fat.
     But the Virginia/South Carolina studies addressed the issue of trust in the estimates. When giving an estimate to a shopper, earn more trust by using the larger percentage if possible. This effect extends beyond numbers. “Very likely” results in more trust than “very unlikely.” It remains even when the estimate is given in the form of a chart.
     Lower trust isn’t all bad. In the studies, those given the lower-probability estimate evaluated all available information more thoroughly, on average. But the lower trust in the physician, salesperson, or presumed expert does mean the consumer is less likely to give that person repeat business.
     If the decision is highly important to the consumer—such as with an invasive medical procedure—giving actual frequencies rather than percentages helps. People will generally work harder to analyze the data, according to research at Bentley University, University of Kansas, and Columbia University. Beyond this, University of Florida and National University of Singapore researchers recommend you round numbers in frequency estimates. Rounded numbers, like 10 or 200, are encountered more often than non-rounded numbers, like 9 or 203, and familiarity builds trust in this case.
     But the best route is to give the shopper both the odds of succeeding and the odds of not.

For your profitability: Sell Well: What Really Moves Your Shoppers

Click below for more: 
Unknot Distortions from Using “Not”
Round Up Benefits for the Shopper
Choose Between Percentages & Frequencies
Wait, Wait, Don’t Tell Me