Confidence and Certainty From Advisors

We like experts who exude confidence. What does that mean?

Posted May 02, 2018

Nick Youngson CC BY-SA 3.0 Alpha Stock Images
Source: Nick Youngson CC BY-SA 3.0 Alpha Stock Images

Confidence sells. When you go to the doctor, you want to feel as though your doctor is confident of your diagnosis and treatment plan.  You want your mechanic to know what is wrong with your car and to communicate that clearly.  Your financial advisor should have a confident set of recommendations for how to invest your hard-earned money. Consistent with this intuition, many studies suggest that people prefer highly confident advisors to less confident advisors.

The term confidence, though, is ambiguous. One aspect of confidence is interpersonal.  If you are confident, then you project an attitude of competence and authority to others.  A second aspect of confidence is certainty. The more confident you are about a particular outcome, the more sure you are that the outcome will happen. 

Do people want their experts to project competence and authority, or do they want their experts to be certain that the outcomes they predict will occur?

This question was explored in a paper in the April, 2018 issue of Psychological Science by Celia Gaertig and Joseph Simmons. 

In one set of studies, sports fans were asked to predict the number of points scored in NBA basketball games or the winner of NBA basketball or Major League Baseball games.  Prior to each prediction, participants were given a prediction by an expert.  The expert signaled that they were not confident in their prediction (saying, “I am not sure, but…”) or they just stated their prediction.  In addition, predictions varied in whether they were certain (like, “The Mets will win the game.”) or uncertain (such as, “There is a 58% chance the Mets will win the game.”).

After making their own prediction, participants also answered questions about how much they liked the advisor and thought that advisor was competent.

Participants liked advisors less when they hedged on their prediction (“I am not sure, but…”) than when they did not.  This effect was obtained across several studies.  Interestingly, participants tended to like predictions better when they expressed uncertainty in the form of a percentage or a range than when they did not.  This effect was particularly strong for percentages or for narrow ranges.  When a prediction range was quite large (“The teams in this game will score between 197 and 257 points”), then people did not like the advisor much.  Participants also didn’t like advisors who used nebulous terms like “probably,” which signal a lack of confidence as well as a lack of certainty.

In a final set of studies, participants saw two expert predictions for sports events or investment performance.  The predictions differed whether the advisor expressed confidence or whether the prediction was certain or uncertain. In these studies, the uncertain predictions were given in terms of a percentage chance a particular team would win a sporting event or whether a particular stock would probably go up or down. 

Participants were asked which advisor they would like to work with again in the future.  Consistent with the previous studies, participants typically chose the advisor with high confidence rather than the advisor with low confidence.  Also consistent with the previous studies, participants chose advisors who gave uncertain predictions rather than certain ones.  

These studies suggest that the two types of confidence have different influences on trust of advisors.  People want advisors to express competence and authority.  However, they recognize that many domains (like sports, medicine, and finance) are impossible to predict with absolute certainty.  So, they actually gain confidence in experts who give good estimates of the likelihood of a particular outcome.


Gaertig, C. & Simmons, J.P. (2018). Do people inherently dislike uncertain advice? Psychological Science, 29(4), 504-520.