Not automatically, and the evidence goes further: among sales staff, personal revenue is a poor predictor of success as a manager. A top salesperson can become an excellent sales manager, but the signs that point to it lie outside the sales league table, and you can check them before you sign off the promotion.
The question nearly always lands at the same moment. The role opens up, your best seller wants it, the team expects them to get it, and an external search looks slow and expensive. This guide gives you what you need to decide on facts: the real risk, the signals that predict a good manager, how to test them and what to do when the answer is no. It complements our page on hiring a Sales Manager.
Key points
- Individual sales performance is a weak predictor of management success: a study of 53,035 salespeople at 214 companies measured it.
- A failed promotion costs you twice. You lose your best seller and gain an average manager, and the team pays the bill.
- The right signals are visible day to day: a habit of selling with others, the ability to explain how they sell, how they handle conflict, and an appetite for the job rather than the title.
- A structured assessment before the decision (in-depth interview, role-plays, competency analysis, KOAN test) costs between €1,500 and €3,000.
- If the answer is no, an expert track keeps your best seller motivated, and an external hire gives the team the manager it needs.
- Under Belgian law, job content and pay are essential terms of the employment contract: you cannot impose a step back, you have to negotiate it.
Why your best seller is the obvious candidate, and why that is a trap
On paper, the logic holds. They know the customers and the objections, they have the credibility of the numbers, and promoting them shows the team that performance pays.
Yet the criterion that singles them out measures something other than what the job requires. Three economists, Alan Benson (University of Minnesota), Danielle Li (MIT) and Kelly Shue (Yale), tested this on data covering 53,035 salespeople at 214 US companies between 2005 and 2011, 1,531 of whom were promoted into management. Their study, “Promotions and the Peter Principle”, published in 2019 in the Quarterly Journal of Economics, reaches two conclusions. Doubling your sales raises your probability of promotion by 14.3%. Once in post, the more the new manager used to sell, the less their team improves: doubling pre-promotion sales corresponds to a 7.5% fall in the sales of each of their direct reports.
The same research highlights an indicator companies rarely look at: collaboration. Salespeople who regularly shared deals with colleagues went on to become better managers, even though this criterion carried little weight in promotion decisions.
These are US figures and do not transfer as they stand to a Belgian SME, but the mechanism is the same everywhere: selling and getting others to sell are two separate skills. We looked at the same dilemma one level up in should you promote internally or recruit an external Sales Director?
Selling versus making others sell: what changes on day one
An operational sales manager keeps a foot in the field, but their result is no longer their own. It is measured by what six, eight or twelve people produce, none of whom sell the way they do. We set out the role in detail in operational sales manager responsibilities. The table below sums up the shifts that trip up promoted sellers most often.
| Dimension | The high-performing seller | The sales manager |
|---|---|---|
| Measure of success | Their own numbers, their ranking | The team’s numbers and each person’s progress |
| Time horizon | This month’s deal, the quarter | The half-year, the year, next year’s team |
| Handling conflict | Avoids it with customers to protect the relationship | Takes it on with the team when results or behaviour call for it |
| Method | Their own, which works for them | Whatever works for each person, sometimes far removed from their own |
| Diary | Customer meetings, negotiation, closing | One-to-ones, field coaching, pipeline reviews, recruitment |
| Recognition | The signed deal, immediate and visible | Other people’s success, slow and shared |
| Relationship with colleagues | Peers, sometimes friends | People they assess, correct and whose bonus they influence |
Two reflexes keep coming back in sellers promoted too early. The first is taking over in a customer meeting as soon as a rep struggles: the deal is saved, and the team learns it does not need to improve. The second is imposing their own method because it has proved itself, without seeing that it rested on a temperament the others do not share.
What a failed promotion really costs
The first cost shows up quickly in the reporting: the top seller’s portfolio is poorly redistributed, and part of their revenue leaves with their habits. The second comes later, when a manager who does not coach slows the whole team down. The third is human: the best salespeople, who have the most options on the market, are the first to leave when management falls short.
Then there is the way back, which few companies plan for. The Belgian Federal Public Service Employment points out (page in French and Dutch) that job content and pay are among the essential terms of the employment contract. A unilateral and significant change to them can be treated as constructive dismissal, and any clause allowing the employer to change working conditions on its own is void. In other words, you cannot simply move a struggling sales manager back into the team. A return to a sales role has to be negotiated, and that negotiation goes better when the subject was raised before the appointment, with help from your employment lawyer.
To put a figure on what is at stake, start from the full package for the role, not just gross salary. Our article on the total cost of a sales manager in Belgium lists the lines to include.
Six signals that predict a good sales manager
None of these signals is enough on its own, but together they tell you far more than the sales ranking, and all of them can be observed before any formal assessment.
They sell with others, not just alongside them
This is the signal Benson, Li and Shue identified. A seller who builds deals with colleagues, shares accounts and brings in pre-sales or a junior already has the habit of succeeding through other people. The brilliant soloist who guards their patch has the opposite habit.
They can explain how they sell
Many excellent sellers work on instinct and cannot describe what they do, so they cannot teach it. Ask them to take apart their last big deal: the stages, the questions they asked, the moment the customer tipped. If the story never gets beyond “I just had a feeling”, coaching will be hard.
They have already helped someone succeed
A junior they supported through onboarding, a colleague they helped out of a bad quarter: that person’s results tell you more than their own numbers. If they have never had the chance, create one before you decide.
They can handle disagreement without damaging the relationship
Sellers are trained to protect the customer relationship. Managers have to correct, refuse a discount, announce an unpopular target. Watch how they handle a disagreement with customer service, logistics or a colleague. Do they work around it, lose their temper, or set out the facts and look for a way forward?
They want the job, not just the title
Why do they want this role? The status, the car, or the wish to develop a team? The honest answer rarely comes at the first question. It tends to emerge when you walk them through a typical sales manager’s week, one-to-ones and pipeline reviews included, and watch how they react.
They accept that others succeed differently
A manager who recognises only one way of selling ends up trying to clone the team. One who accepts that a quieter colleague wins through preparation, where they win through ease, will adapt their coaching to each person.
Be wary, on the other hand, of false signals: length of service, confidence in meetings, popularity with the team or the candidate’s own insistence. They reassure, but they predict very little.
How to assess them before you decide
The aim is to replace a gut feeling with a reading you can defend to the candidate and to the team. Four steps are enough.
1. Define the role before you look at the candidate
What do you expect from the sales manager in twelve months’ time? How many people will they lead, how much personal selling will they keep, which indicators will they be judged on, which decisions will be theirs? Without this framework, you end up assessing the person against themselves. The new manager’s objectives are part of it, and we explain how to build them in how to set sales manager objectives.
2. Give them a real-life trial
For two or three months, give them a limited, visible management responsibility: onboarding a new rep, running the weekly pipeline review, leading a cross-functional sales project. You will see how they pass on knowledge, follow up and make calls. Some discover at this stage that they do not enjoy it, and it is better to find that out before the appointment than after.
3. Use an external assessment
An outside view removes proximity bias: you know this seller too well to assess them dispassionately. Our assessment for internal promotion rests on four components: an in-depth interview, role-plays and a case study, a competency analysis and the KOAN personality test, the tool we have used for 30 years. KOAN reads three dimensions: competencies, drivers (what moves the person forward and what holds them back) and behavioural dynamics, meaning how they react under pressure, in a team and in the face of change. Its sales competency model also covers influencing strategies, methods and example to others, all of which matter directly in the move into management.
| Format | Duration | Depth of analysis | Fee |
|---|---|---|---|
| Small | 1 hour | Focused profile reading | €1,500 to €3,000 |
| Medium | 2 hours | In-depth analysis | €1,500 to €3,000 |
| Large | 3 hours | Most comprehensive analysis, for a critical role | €1,500 to €3,000 |
Most of the value lies in the debrief, which pinpoints the gaps between the profile assessed and the target role. When several employees are in the running, or for a manager already in post, our assessment of managerial skills follows the same logic.
Expert view
An assessment that ends with a PDF report has no value. Ours rests on three moments: the deep-dive interview, competency analysis on real cases and role-plays, and the KOAN personality test. And above all, the debrief: spoken, structured, actionable. What you walk away with is a clear read on competencies, drivers, and gaps versus the target profile. Not a score. A decision.
4. Benchmark against the market
If the stakes justify it, assess your internal candidate alongside two or three external profiles, using the same grid. If they are chosen after that comparison, they gain a legitimacy a straightforward appointment would never have given them. If not, they know why, and you know what the market has to offer.
If the answer is no: three options that keep your best seller
Build an expert track
A seller who should not manage still needs to progress, or they will look elsewhere for the title you have withheld. An expert track offers progression without a team: strategic accounts, a reference role for onboarding newcomers, a seat in offer and pricing decisions. Without a proper job title and package, it will be read as a consolation prize.
Hire the sales manager externally
An experienced manager arrives with proven coaching and steering methods, and with no shared history with the team. The specific risk of an external hire is reduced by the quality of the brief and by assessing the finalists. On our assignments, the average time from client signature to candidate signature is 12 weeks. We work on a retainer basis, with a six-month replacement guarantee.
Cover the gap with an interim sales manager
When the role cannot stay empty during the assessment or the search, an interim manager holds the team together and prepares the ground for the permanent hire. We look at when this option makes sense in interim sales manager: when to bring one in.
If the answer is yes: secure the first six months
A well-assessed promotion can still fail if it is poorly prepared. Five decisions make the difference.
- Announce the appointment to the team with the scope, the objectives and the reasons for the choice, then hold a one-to-one with each rep within the first month.
- Cut their personal portfolio decisively, so they have time to manage instead of carrying on selling.
- Review their package so they do not earn less than they did as top seller.
- Train them in management from the day of the appointment, not after the first conflict. Our management training combines classroom sessions with field coaching, with modules on coaching, motivation, feedback and performance reviews.
- Agree in writing with them on checkpoints at three and six months, and on the options available if the role does not suit them.
Before you sign off the promotion
Your best seller may become your best manager, or the departure you did not see coming, followed by two more. The difference is decided before the appointment, on facts rather than gratitude. If you are torn between promoting and recruiting, we can assess your internal candidate, benchmark them against the market or run the search: our page on sales manager recruitment in Belgium explains how we work.
Frequently asked questions
Why do the best sales reps often make poor managers?
Because the job changes in nature: a seller succeeds through personal performance, a manager through other people’s. Taking over a deal or avoiding conflict, reflexes that work in sales, become obstacles when you have to coach and correct a team.
What makes a good sales manager?
Developing reps who sell differently from them, explaining a method, handling disagreement, steering with indicators and recruiting well. Solid sales experience helps, but it replaces none of these skills.
What are the traits of a great salesperson?
The KOAN sales competency model we use lists ten, including customer orientation, a results-oriented approach and perseverance. These traits remain useful in management, but a manager must also pass on knowledge, organise and help others succeed.
How can you tell whether a salesperson could become a sales manager?
Look at their collaboration habits, their ability to explain how they sell, how they handle conflict and what really motivates them. Give them a limited management responsibility for a few months, then have your reading confirmed by a structured assessment.
Can you reverse a promotion that does not work out?
Not unilaterally. Under Belgian law, job content and pay are essential terms of the employment contract, and changing them significantly without agreement can amount to constructive dismissal. A return to a sales role has to be negotiated, ideally on terms discussed before the appointment.
How much does an assessment before an internal promotion cost?
At Archetype, an individual assessment costs between €1,500 and €3,000, depending on the format (one, two or three hours) and the depth of analysis required. It ends with a spoken, structured debrief.
