The Ackerman model is a four-tier offer method: aim for 65% of your target, then move up to 85%, 95% and finally 100%, using precise, non-round figures (for example £37,450 rather than £37,000). The diminishing concessions give the other side the feeling of having wrung out the maximum.
Grounding in the source schoolSchool grounded in research and field practice
Indicative profile: it situates the “Managing concessions” family as the FBI · Chris Voss school practises it, not this technique taken in isolation. Techniques from the same family and school therefore share the same profile. NEGOCOACH editorial rating out of 10, non-experimental · the higher the “relational risk” value, the more costly the technique is to the relationship.
NEGOCOACH assessment
How to read this rating
Tactical potential 6.3/10 (effectiveness, impact, discretion) and vigilance low (relational and ethical risk): two distinct readings, deliberately never merged into a single score that would reward risk. NEGOCOACH editorial rating calibrated from the “Managing concessions” family and the “FBI · Chris Voss” school. Each criterion is rated out of 10; click to understand what it measures.
Effectiveness8/10 · Very high
How far the technique can carry the negotiation in the intended direction when it is well executed.
Psychological impact6/10 · High
Strength of the effect produced on the counterpart's perceptions, emotions and decisions.
Discretion5/10 · Moderate
How hard it is for the other party to notice the technique is being used. A high value = very discreet.
Preparation6/10 · High
The information, analysis and rehearsal required upfront to use it effectively.
Relational risk3/10 · Low
Potential cost to the relationship and to trust if the technique is spotted, refused or fails. A high value = riskier.
Ethics7/10 · High
Moral acceptability: fairness, transparency and respect for the counterpart's autonomy. A high value = more defensible.
Level of evidence
School grounded in research and field practice
The school this technique stems from combines academic work with long field practice. This indicator qualifies the school, not this technique taken in isolation.
Indicative NEGOCOACH editorial rating, for teaching purposes. For “Relational risk”, a high value signals a cost to the relationship, not a quality.
Summary of the ACKERMAN MODEL
Origin & history
The method is named after Mike Ackerman, a former CIA agent who became a hostage-release consultant and founder of the Ackerman Group in Miami. Faced with kidnappers demanding colossal ransoms, he devised a system of calibrated offers, 65, 85, 95 then 100% of the real budget, to convince the other camp that he had reached the absolute limit. The FBI adopted the method, and Chris Voss popularised it with the general public. Born in the extreme world of kidnapping, it proved formidably effective in any numbers-based negotiation, from buying a car to a corporate merger.
Definition and principle
Systematised by the FBI school of negotiation, this technique combines anchoring, calibrated concessions and the effect of precise figures (perceived as considered and non-negotiable). Each tier smaller than the last signals that you are approaching your real limit, which pushes the other party to close.
Concrete examples of application
Application by context
The same technique, across several negotiation settings
For a contract valued at £100,000, the buyer anchors at £65,000, then proposes £85,000, £95,000 and ends at £97,850. The final tiny increase and the precise figure convince the seller to accept.
Context 2 / 6
Labour negotiation
In a collective pay negotiation, the unions first ask for a 6% rise, then successively accept 4%, 2.5% and 2.1%, the last minuscule step signalling that they have reached their floor.
Context 3 / 6
Crisis management
A negotiator secures the release of hostages in diminishing batches (ten, then four, then two, then one), each smaller concession lending credibility to the idea that he has nothing left to give.
Context 4 / 6
Political negotiation
On a budget, one party proposes a 65% cut, then 85, 95 and 98%, the tightening tiers giving the opponent the feeling of having obtained everything.
Context 5 / 6
Real-estate negotiation
Faced with a property at £300,000, the buyer offers £250,000, then £275,000, £290,000 and £293,500. The precise figures and the narrow final step carry the seller's decision.
Context 6 / 6
Family negotiation
In a division of assets, one party offers to take on 65% of the costs, then 85, 95 and 97%, the diminishing progression making the agreement acceptable to all.
Counter-techniques
Spot and neutralise this technique
Negotiation is also played on defence. Here is how to recognise this technique when it is used against you, and turn it around.
Detect
The signals that give it away
A "huge" concession on a worthless point
Last-minute nibbling
A visibly unbalanced exchange
Neutralise
The counters that defuse it
Quantify the real value of each point
Never concede without a counterpart
Keep a reserve for the end
Turn around
Turn it into an advantage
Answer any request with a symmetrical one: "If I do that, what do you do?"
The trap to avoid
Giving for free to "make a gesture".
Strengths and Weaknesses
The model disciplines the escalation of concessions and exploits two powerful levers: the shrinking of the steps and the precise figures. Its limitation: it assumes you know your real target and your margin; against a seasoned negotiator who recognises the pattern, the effect wears off.
When to use this technique?
Perfect for numbers-based negotiations (price, salary, budget) where you have margin and time. To be avoided when only a single exchange is possible or when the relationship demands transparency rather than haggling.
Objectives of the technique
Set a low anchor (initial offer at 65% of the target price) to shift the zone of agreement in your favour.
Structure your progression in diminishing concessions (65 85 95 100%) to signal that you are approaching your true limit.
Prompt a counter-offer from the other party at each tier before moving, rather than negotiating against yourself.
Use non-round, precise final amounts to lend credibility to having reached the end of your margin.
Add a non-monetary trade-off at the final tier to make your limit tangible and unlock the agreement.
Famous cases
Diplomatic · Hostage ransoms at the FBI: Chris Voss, former lead negotiator for international hostage-taking at the FBI, recounts in “Never Split the Difference” that for years he applied the formula inherited from agent Mike Ackerman when facing kidnappers. Rather than splitting the difference, he started from a deliberately low offer (around 65% of the sum sought), then moved up in ever smaller tiers, each time getting the kidnappers to formulate a counter-demand. The diminishing concessions signalled that he was scraping the last available margin, and the final amount, precise and non-rounded, made credible the idea that there was nothing left to obtain.
Everyday life · Buying a used car: A buyer is after a car listed at £10,000, with a personal target price of £8,000. He opens at £5,200 (65% of his target), justifying it calmly on the basis of condition and market, and invites the seller to react. After exchanges, he moves up to £6,800 (85%), then £7,600 (95%), and finally £7,987 (100%, a precise amount), adding that he will take the vehicle as it stands without asking for a service. The ever-shorter tiers and the non-round figure signal that he is genuinely at the end of his budget.
Common mistakes
Making concessions of constant or increasing size, which destroys the “I am reaching my limit” signal at the heart of the method.
Stacking your own offers without having obtained a counter-offer: you end up negotiating against yourself.
Opening with an anchor so low that it seems insulting or unrealistic, which antagonises the other party or breaks off the dialogue.
Announcing a round final amount (£8,000), less credible than a precise figure (£7,987) meant to reflect tight calculation.
Forgetting the non-monetary trade-off at the final tier, which makes the limit tangible and helps the other side accept without losing face.
Applying the percentages mechanically without empathy or skilful “no”s, turning a relational tactic into a mere trial of strength.
Limitations and ethics
The model adds no value to the offer: it stages the manner in which you give ground. That is where the ethical question lies, and it is subtler than it appears, because the method has a perfectly healthy side: imposing on yourself a calculated trajectory of concessions before the session protects you from yourself, from the need to please and from concessions given away in the emotion of the moment. Used this way, it is personal discipline. The questionable side lies in the signals it manufactures. The precise figure (£37,450 rather than £37,000) is effective because it suggests a calculation that, most often, does not exist. The diminishing concessions are effective because they signal a limit you are approaching, whereas the final tier was decided in advance. The technique does not lie about the price, it lies about its own effort, and the other side pays a premium of satisfaction for a victory that was conceded to it. Structuring your concessions so as not to give ground at random is discipline; manufacturing the signs of a limit you have not reached is a charade.
Scientific foundations
Chris Voss, Tahl Raz (2016) Never Split the Difference: Negotiating As If Your Life Depended On It HarperBusiness
Amos Tversky, Daniel Kahneman (1974) Judgment under Uncertainty: Heuristics and Biases (anchoring and adjustment) Science, vol. 185, DOI: 10.1126/science.185.4157.1124
Quick exercise
Test yourself before answering
Answer in your head, then reveal the solution. Memory is built through active recall.
1Quels signaux doivent vous alerter ?
A "huge" concession on a worthless point
Last-minute nibbling
A visibly unbalanced exchange
2Quelles parades appliquer ?
Quantify the real value of each point
Never concede without a counterpart
Keep a reserve for the end
Frequently asked questions
The questions we get most
What is the "The Ackerman Model Technique" technique?
The Ackerman model is a four-tier offer method: aim for 65% of your target, then move up to 85%, 95% and finally 100%, using precise, non-round figures (for example £37,450 rather than £37,000). The diminishing concessions give the other side the feeling of having wrung out the maximum.
Is the "The Ackerman Model Technique" technique ethical?
Yes. Used in good faith it stays within a fair negotiation: it structures the exchange without deceiving the other party. Being transparent about your intentions strengthens the long-term relationship.
How do you defend against "The Ackerman Model Technique"?
Giving for free to "make a gesture". The right reflex: quantify the real value of each point.
What is the "The Ackerman Model Technique" technique based on?
NEGOCOACH does not assess the experimental validation of this technique in isolation. What we document is the grounding of its source school (FBI · Chris Voss): school grounded in research and field practice. Full detail is in the "At a glance" section of this page.
Practise with AI
Three ready-to-use prompts
Copy, paste into your assistant, replace the [brackets]. Works with ChatGPT, Claude, Gemini, Mistral, Perplexity.
Prepare
Build your plan before the meeting
You are an expert negotiation coach. Help me prepare to use the "The Ackerman Model Technique" technique in the following situation: [describe your situation]. Give me: the conditions for success, a 3-step script, my counterpart's likely objections and how to answer them.
Play the role of my counterpart in a negotiation. I am going to test the "The Ackerman Model Technique" technique. React realistically and with resistance, do not give in too quickly, then at the end analyse my performance and suggest 3 concrete improvements.
Here is how my negotiation went: [paste the exchanges]. Analyse whether the "The Ackerman Model Technique" technique was used well, what worked, the mistakes made, and spell out precisely what I could have done better.
Founding works of the 🕵️ FBI · Chris Voss school this technique belongs to.
Never Split the Difference
Book
C. Voss & T. Raz · 2016
The FBI's hostage-negotiation methods transposed to business and everyday life: tactical empathy, mirroring, labeling, calibrated questions. An emotional, counter-intuitive approach to persuasion.
Stalling for Time, My Life as an FBI Hostage Negotiator
Book
G. Noesner · 2010
The account of twenty-three years of crisis negotiation at the FBI by the head of its unit. A demonstration of the power of listening, patience and de-escalation in the most tense situations.
Chris Voss, "Never Split the Difference", 2016, FBI crisis negotiation.
The author
Author
On video
See the technique in action
Videos to picture The Ackerman Model Technique and anchor it through examples.
The Ackerman model is a four-tier offer method: aim for 65% of your target, then move up to 85%, 95% and finally 100%, using precise, non-round figures (for example £37,450 rather than £37,000). The diminishing concessions give the other side the feeling of having wrung out the maximum.
The right reflex
Answer any request with a symmetrical one: "If I do that, what do you do?"
Never do this
Giving for free to "make a gesture".
6.3/10 tactical potential Low vigilance School grounded in research and field practice
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