Make the case with proof that is the buyer's own: a team inside the account already getting the result, or a comparison with respected peers that the champion circulates before your proposal.
Your case studies come from other companies, and the buyer's team has the same answer to every one of them: we are different.
Make the case with proof that belongs to the buyer. There are two places to find it.
The first is inside the account. There is often a team already doing a version of what you sell: a branch that built a spreadsheet to track what the system does not, a department running an unofficial pilot, one manager whose numbers beat everyone else's for reasons nobody has looked into. Find that team, work out what they do differently, check that the rest of the organisation could copy it, and make the deal about scaling them, not about your product. Chip and Dan Heath call this finding the bright spots in Switch, taking the idea from Jerry Sternin's positive deviance work in public health.
The second is outside the account. Before any proposal, the champion compares the company's performance with organisations it respects, shares that comparison with the people who matter, and only then offers ways to close the gap. Paul Nutt, who tracked hundreds of decisions inside organisations, calls this intervention, and it was the most reliable way of making a decision stick that he found.
Neither is published as a sales move. Putting them together for a deal is the library's own step.
The six steps, as the BMJ prints them. David Marsh, Dirk Schroeder, Kirk Dearden, Jerry Sternin and Monique Sternin set out the sequence in 2004. Define the problem. Find four to six people who got an unexpectedly good result despite facing the same risks. Interview and watch them to find what they do that others do not. Confirm those behaviours are uncommon and within reach of everyone else. Design ways for the community to adopt them. Then monitor the results. The fourth step matters: a behaviour counts only if the people who do not do it yet could.
The question a Goldman Sachs leader opened with. In Richard Pascale and Jerry Sternin's account in Harvard Business Review, the head of the private wealth unit asked more than 300 advisers whether some teams, with similar territories and prospects, were thriving in the same hard market. Six respected advisers spent two months finding five practices, small teams took one practice each to every office, and the eleven regional offices were ranked on adoption, with the ranking published and no penalty for not adopting.
What intervention looked like in Nutt's cases. The manager compares current performance with standards taken from respected organisations, spends time with key people explaining where those standards came from, documents the gap, and only then offers ways to close it. His example is a board that listed what comparable boards were responsible for, saw it was too involved in day-to-day operations, and reorganised itself.
Nobody has measured it on the buyer's side. No study compares deals where the seller found and scaled a bright spot inside the customer, or gave the champion a peer comparison, with deals where the seller argued the case from outside. Nutt's decisions were all internal, with no supplier involved, and whether a comparison supplied by a vendor works as a standard or reads as marketing is untested.
Genentech, on the seller's side. Pascale and Sternin report that six months after the 2003 launch of the asthma drug Xolair, two salespeople out of 242, covering Dallas and Fort Worth, were selling twenty times more than their peers. They had worked out that allergists and paediatricians would not take on an infusion procedure just because a rep brought more clinical data to a sit-down call, so they walked doctors, nurses and administrators through preparing and giving the drug and through the insurance paperwork. When Genentech had their manager describe the techniques to other managers on a conference call, the other teams took them up only partly and slowly. The authors are the method's advocates writing up their own work, there is no comparison group, and the variation was between the seller's own reps, not inside a buying organisation.
Vietnam, and the one randomised comparison. The BMJ paper reports a 74% fall in severe malnutrition among children under three in positive deviance programmes in the early 1990s, and a randomised comparison of 240 malnourished children, half in villages that ran the programme and half in villages that did not, measured monthly for six months and again at twelve. The children in the programme grew better, ate more often and larger portions, and had fewer chest infections. The same paper warns that positive deviants are typically 1% to 10% of a population, and rare examples are costly to find.
The organisational cases, all reported by their advocates. In the HBR article, teachers in Argentina's Misiones province, where 56% of children finished primary school against 86% nationally, copied the agreements the best schools made with parents, and dropout reportedly halved a year later. At Goldman Sachs the process ran 18 months, and average output per adviser nearly doubled. Pascale and Sternin ran both projects, and neither had a comparison group. Ruth Baxter and colleagues' review of 22 positive deviance projects in healthcare organisations found the research quality low, comparison groups rare, and most projects stopping once they had found the positive deviants.
Set the standard first, argue second. Paul Nutt's study of 356 decisions in medium and large organisations in the US and Canada, published in 1999, recorded how each manager put the decision into practice and whether it stuck. Persuasion, expert argument plus selling, was used in nearly 40% of decisions and stuck 56% of the time. Intervention, setting the standard first, was used in 7% and stuck 96% of the time. Nutt's reading is that managers saw persuasion as the low-risk option and were wrong. Nothing was randomised.
Whether local proof beats general proof is not settled. In Noah Goldstein, Robert Cialdini and Vladas Griskevicius' hotel experiments, a card about guests who had stayed in that same room got 49.3% of guests to reuse towels, against 37.2% for the standard environmental appeal. Gerd Bohner and Lena Schlüter's replication went the other way in its first study, 78.0% for the same-room card against 85.6% for the general one, and found only a weak, unreliable trend in the original direction in its second.
Everything measured comes from public health, schools and firms changing their own staff, and in the business cases the people reporting the numbers ran the projects, with no comparison group. Nobody has tested a supplier pointing at a customer's bright spot, or a comparison that arrives from a supplier, which is the part most likely to break. And positive deviants are rare, 1% to 10% of a population, and expensive to find.
Before you build another case from your other customers, ask whether anyone inside the account already gets the result, check that what they do could be copied, and let the champion put a comparison with respected peers in front of colleagues before your proposal arrives. Inside organisations, setting the standard first outlasted argument by a wide margin. With a supplier involved, nobody has measured it. Keep what you find as their evidence, because the moment it becomes your case study you are back to arguing.