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The Dunning-Kruger Effect in B2B Sales: When Sales Confidence Gets Ahead of Sales Competence

 

Your salesperson may not know they have a sales-skill problem. That’s exactly what makes it so hard to fix. Moreover, a salesperson tells you: “I’m a very good salesperson.” They back it up with fifteen years of experience. They know their customers. They know their products and market. Strong personality. Millions of dollars sold. So, you ask them to rate their discovery skills. They share: “Nine out of ten.”

Then you listen to five customer calls. The salesperson talks too much. ( we coach sales to speak 30% of the time and clients 70%) The questions are superficial. Business impact is never quantified. The customer never explains why the problem matters. The salesperson presents a solution before understanding the problem.

The salesperson thinks they’re conducting discovery. They’re conducting a product interview.

When we assess sales teams, we often receive resistance for two reasons. First, someone on the team knows they lack the skills and doesn’t want the assessment to reveal gaps in their sales skills, beliefs, or motivations. The second is one of confidence. They feel overly confident and feel the assessment is a waste of “selling time.”

I experienced this with a team early this year. ( I just did not know what to call it) Two sales team members refused to complete their sales effectiveness assessment. Once the CRO and I convinced them we plan to use the results as a sales training and coaching tool, they both complied.

What I found interesting was that the salesperson knew they lacked selling skills but had very strong product and market knowledge. They had a strong desire and outlook, strong sales DNA; they just never received foundational sales skills. They wanted help for years, but they worried that asking for training and coaching would have negative repercussions.

The second was the sales manager, their once top-producing salesperson. She had a strong level of confidence in her sales and sales management skills and felt this step in the no-smoke-and-mirrors sales enablement process was a waste of time, insulting even to ask her to take the assessment. She has been in this industry for over 20 years and honestly felt she was in the top 1% of sales managers.

The CEO and CRO wanted my help because the sales team missed their growth goals three years in a row. They were at a plateau. They heard me speak about how plateaus are more dangerous than declines, and they wanted to know why their sales had stalled and what we could do to improve the team’s sales effectiveness.

The sales manager had strong sales skills but lacked core sales manager skills like coaching, recruiting, and pipeline management. She had limiting beliefs, like that it wasn’t her job to motivate her team; they should be motivated by their compensation structure. She had strong confidence but didn’t know what she didn’t know. ( my very first blog post)

I started researching what I experienced because it happened again and found that it is not unusual and has a name: The Dunning-Kruger Effect. So I wanted to share what I found in hopes it helps sales teams improve their sales effectiveness.

This is where the Dunning-Kruger Effect gets interesting for B2B sales leaders. 

In 1999, psychologists Justin Kruger and David Dunning published Unskilled and Unaware of It in the Journal of Personality and Social Psychology. They studied how well people could judge their own performance in areas like humor, grammar, and logical reasoning.

The finding that stuck with me was that participants in the bottom quartile badly overestimated themselves. People scoring around the 12th percentile put themselves around the 62nd. Kruger and Dunning explained that the skills required to perform well can also be the skills required to recognize poor performance.

No Smoke and Mirrors Truth: If you don’t understand what excellent looks like, you can’t see how far you are from it.

That’s a powerful idea for sales leadership. But it comes with a caveat, and skipping it would be dishonest.

Later research has pushed back hard on the simple version of this story. Follow-up work by Ehrlinger and colleagues found real evidence that poor performers lack insight into their own shortcomings, even when incentives push them to be accurate. But a 2022 registered report from McIntosh and colleagues tested the theory directly and found the opposite of what the popular version claims: poor performers were less confident than good performers, not more. They concluded that the classic pattern is largely a statistical artifact, not proof that incompetent people are inherently overconfident.

So I wouldn’t use Dunning-Kruger as a label for a salesperson.

I’d use it as a management question: How accurately does this salesperson understand their own capability?

That’s the useful version.

B2B Salespeople have a self-assessment problem

Salespeople constantly judge themselves. “I’m good at discovery.” “I’m good at closing.” “I’m good at building relationships.” “I’m good at negotiating.” “Customers trust me.” “I don’t need training.”

But how do they know? That’s the problem. Confidence isn’t evidence.

A meta-analysis published in Academy of Management Learning & Education found that people’s self-assessed knowledge has only a moderate relationship with actual learning and performance, and it’s a much stronger predictor of motivation and satisfaction than of real competence. The researchers recommended a limited role for self-assessment in evaluating what someone knows.

That should get every sales leader’s attention, because most organizations assess salespeople by asking salespeople to assess themselves. Some organizations ask the sales managers and leaders to assess their team quarterly or every six months against a defined list of sales competencies. These sales managers and leaders often haven’t received sales leadership training, so they compare each person’s skills to their own from when they were in the sales role and include recent observations of the salesperson with customers. Some use forced ranking systems to rate each team member on a scale.

The salesperson who says, “I’m a 9”

Ask your team to rate themselves 1–10 on prospecting, discovery, creating urgency, value creation, executive conversations, negotiation, closing, account development, competitive selling.

Now compare those numbers to actual evidence. Run a sales effectiveness assessment. Listen to calls. Review opportunities. Pull win/loss data. Talk to customers or read voice-of-customer insight reports. Look at pipeline movement, conversion rates, new-logo acquisition, gross margin, retention.

No Smoke and Mirrors Truth: Perception versus performance. That gap is where the real diagnosis begins.

The confidence-competence gap

Salesperson A. Self-rating: 9/10. Strong personality, very confident, 20 years of experience, excellent product knowledge. But: 70% of talk time in customer meetings, weak discovery, few business-impact questions, poor prospecting discipline, discounts early, almost no account expansion, blames price when deals stall.

Salesperson B. Self-rating: 7/10. More reserved, asks for coaching, practices often, reviews lost deals. But: excellent discovery, strong questioning, consistent prospecting, quantifies customer impact, builds multiple relationships, creates real next steps, grows existing accounts.

Which one do you want? The answer is obvious on paper. But organizations routinely promote, reward, and listen to confidence, because confidence is visible and competence isn’t.

B2B Sales Experience can make the problem worse

I have found one of the most dangerous sentences in sales is: “I’ve been doing this for 20 years.”

Experience matters, but it doesn’t automatically drive development. A salesperson can repeat the same behavior for two decades. If that behavior works reasonably well, it gets reinforced: see, I’m good at this.

But markets change. Buyers change. Competitors change. Technology changes. Buying committees change. The salesperson who won on features and relationships 15 years ago may struggle today when customers expect business insight, measurable value, and engagement across multiple stakeholders.

A 2026 study in the European Business Review examined predictors of B2B salesperson performance and identified dozens of validated subdimensions across six performance areas. The point is sales leaders forget sales performance is multidimensional. It’s not just personality, tenure, likeability or charisma.

The relationship salesperson can be especially vulnerable

“My customers love me.” Probably true. But relationship strength doesn’t automatically mean sales effectiveness.

Ask: What percentage of your customers buy everything they could buy from you? How many new problems have you uncovered? How many new stakeholders have you developed? How much share of wallet do you own? How much revenue comes from new customers? How much margin are you protecting?

I have heard: “We have most of the business.” However, voice of customer interviews revealed they had about 33% of the opportunity dollars

A salesperson can have great relationships and still leave significant revenue on the table. That’s not a relationship problem. It’s a sales-skill problem.

For example, let’s say a sales rep has a great relationship and feels they need to be liked. Often, they do not ask the questions we need to be seen as an industry expert in fear they may hurt the relationship.

The “market is bad” sales defense

Another warning sign. Revenue declines. The salesperson says, “the economy is bad.” Maybe. Then you find out competitors are growing. Now the question changes: what are they doing that we’re not? You do not have a market problem; you are hearing an accountability problem.

The economy affects everybody. Tariffs affect everybody. Interest rates affect everybody. But they don’t affect every salesperson equally. A strong sales assessment separates market problems from company problems, from sales-process problems, from sales-skill problems, from sales-execution problems. Without that separation, external circumstances become a convenient cover for internal performance gaps.

Research says sales performance is complicated

This isn’t just about motivation. A systematic review of more than 250 published articles on salesperson performance found that effectiveness is shaped by personal, organizational, coworker, buyer, and situational factors. A broader meta-analysis of 139 independent B2B sales studies identified 31 separate determinants of sales success across the salesperson, the organization, the customer, and the environment.

That means a sales leader shouldn’t jump straight to “we need more training.” The real question is: what is actually causing the gap?

Current Gartner research makes the same point, recommending a root-cause assessment using a “skill, will, hill” framework to separate capability problems from motivation problems and from friction built into the job itself. A salesperson who isn’t prospecting could have a skill problem — they don’t know how. A will problem — they know how but don’t want to. Or a hill problem — their territory, technology, process, or workload makes it unnecessarily hard. Treating all three with the same training program is a mistake.

Coaching is where the gap becomes visible

The fix isn’t telling a salesperson, “you’re not as good as you think you are.” That creates defensiveness. The better move is to create evidence. Listen to the call. Review the opportunity. Compare the self-assessment to the observable behavior. Then ask: “What do you hear?”

That question does the work. Instead of the manager announcing what’s wrong, the salesperson discovers the gap themselves. And self-discovered awareness is what actually changes behavior.

Coaching is becoming more important, not less

Salesforce’s State of Sales research reports that a strong majority of reps say they’re more likely to hit target with a coach or mentor — yet close to half say they rarely get feedback on sales conversations, and roughly the same share say they don’t get enough chances to role-play important conversations before they happen with a real customer.

Salespeople want coaching. Managers don’t always have the time to give it. Gartner’s 2025–2026 research pushes toward data-driven, more targeted coaching rather than trying to coach everyone on everything.

That’s where technology and AI can help — but they don’t replace the manager. They can surface patterns. The manager still has to interpret them, coach the actual behavior, and hold the salesperson accountable.

The No Smoke & Mirrors approach to improving sales effectiveness

This is why I don’t believe the first move in improving a sales organization should automatically be training.

Assess first.

I want five sources of sales skill evidence:

  1. Salesperson self-assessment — what they believe they’re good at, and where they think they need help.
  2. Sales Effectiveness Assessment– skills, motivations, and beliefs based on knowledge from 3rd party
  3. Actual sales behavior — what happens in customer meetings. What questions get asked. How much the salesperson talks. Whether they diagnose, create urgency, and establish value.
  4. Customer voice — why customers actually bought, why they didn’t, what they value, what frustrates them about the sales experience.
  5. Transaction data — who’s producing, which customers are profitable, where opportunities die, conversion rates, pipeline stalls.
  6. Manager observation — what the manager sees repeatedly, and whether that’s backed by objective evidence or just an opinion.

Build a B2B sales MRI

Before writing the prescription, get the diagnosis. Think of it as an MRI of the sales organization — skills, process, beliefs, behaviors, pipeline, customer experience, manager effectiveness, market conditions, data.

Then compare what salespeople think they do against what they actually do. That’s where Dunning-Kruger becomes useful — not as a label, but as a diagnostic lens.

Many teams also compare sales team member data to top-performer data. You know your top two performers carry over 60% of revenue. If you ask them what they do or how they do it you may just get a shoulder shrug. Assess them, and you will know exactly the skills, beliefs, and motivations required to be a top performer on your team, in your industry. Think of it a cloning your known top performers.

The goal isn’t less confidence

We don’t want timid salespeople. We want confident salespeople whose confidence is calibrated to reality. From my experience, the shortest path to good confidence is training and practicing the skills.

The ideal salesperson can say “I’m very good at discovery” and prove it. They can say, “Negotiation is one of my weaker skills,” and know why. They can say “I need help with executive selling” and ask for coaching. They can say “I lost this opportunity because I didn’t uncover the business consequence early enough.”

That’s professional self-awareness. And it’s coachable.

One outcome of a sales assessment is that overly confident sales team members discover they have sales skills that need improvement. The assessment shows how they compare to others in the industry and to everyone who has taken it globally. Often, overly confident salespeople are also highly competitive.

For example, we assessed a sales engineer with 25 years of experience. He told the sales VP it was a waste of his time. When I reviewed his results, we found he struggled to speak with decision-makers and spent too much time with gatekeepers. In our course on getting past the gatekeeper, he was by far the most engaged and shared stories with other salespeople. Had he not seen his assessment, he might not have attended the training, or he might have attended but not engaged with or applied it. (He learned why he did not know)

The best B2B salespeople know what they don’t know ( and are motivated to improve)

This might be the biggest lesson for sales leaders. The best salespeople aren’t the ones who think they know everything — they’re the ones who stay curious. They ask better questions. They review lost deals. They listen to customers. They ask for feedback. They practice and study their craft. They listen to podcasts, read books and blogs. ( hopefully mine!)

No Smoke and Mirrors Truth: Experience without reflection becomes repetition. Confidence without calibration becomes complacency.

Six questions for every B2B sales leader

Before you spend another dollar on sales training, ask:

  1. How accurately do our salespeople assess their own skills?
  2. What did we learn in the sales effectiveness assessment about skills, beliefs and motivations?
  3. What objective evidence do we have?
  4. Where is the biggest gap between perceived competence and actual performance?
  5. Are we dealing with a skill problem, a motivation problem, or an organizational barrier?
  6. Are our managers spending enough time coaching the specific behaviors that drive revenue?

If you can’t answer those, you probably don’t have a training problem. You have a diagnosis problem.

That’s where the No Smoke & Mirrors approach begins: Assess. Diagnose. Train. Coach. Measure.

No smoke. No mirrors. Just evidence, behavior, and results.
Let’s schedule a call to discuss our no smoke and mirrors process and how, working together, we can increase your revenue and margins per sale.

 

Research behind this article

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