Look at most promotional briefs and you will find a wishlist. The campaign is meant to drive trial, reward loyal buyers, lift basket size, collect first-party data and make the brand feel a bit more fun — all from one mechanic, one prize pool and one eight-week window. It reads like ambition. It usually behaves like confusion.
The promotions that actually move a number tend to be the ones that picked a single job and built everything around it. That discipline has a name in The Shelf Truth — the One Job Rule — and it is the cheapest thing in promotional marketing, because it costs nothing and saves you from spending budget in five directions at once.
What is the One Job Rule?
The One Job Rule says a promotion should be designed to do one thing well, and judged on whether it did that one thing. You pick the objective first, then choose the mechanic, the prize and the level of friction to serve it. Anything that does not serve the one job is either neutral or quietly working against it.
There are really only five jobs a promotion can do, and they pull in different directions. A Breaker is built for trial — getting someone who has never bought the product to try it once. A Builder is for frequency — getting an existing buyer to come back sooner. A Loader is for basket size — getting a bigger shop in a single visit. A Harvest is for data — trading a reward for permission to keep talking to the customer. And a Keeper is for loyalty — giving regular buyers a reason to stay. The reason you cannot do all five at once is that each one wants a different shopper to do a different thing, and a single offer cannot send five signals without blurring all of them.
Trial is the clearest example. If the job is to break a non-buyer into the category, the entry barrier has to be almost nothing, because you are asking a stranger to take a punt. The moment you bolt on a data-capture form or a minimum-spend threshold to also serve the Harvest or the Loader, you have made the Breaker worse. The person you most wanted — the curious first-timer — is the one who drops out first.
Pick the job before you pick the mechanic
The most common mistake is choosing the mechanic first. Someone in the room wants an instant win because it sounds exciting, or a prize draw because the last one ran smoothly, and the objective gets reverse-engineered to fit. You can see the gravity of this in the live market: of the roughly 170 Australian promotions Trevor Services is tracking at the moment, the single-entry prize draw is by far the most common mechanic, well ahead of gift-with-purchase and instant win. Prize draws are popular partly because they are genuinely flexible and partly because they are the safe default — the thing you reach for when nobody has decided what the promotion is actually for.
Across the campaigns Trevor Services has run, the spread looks similar — simple-entry draws and sweepstakes make up the bulk, with gift-with-purchase and cashback behind them. None of those mechanics is right or wrong on its own. A prize draw is a fine Harvest and a poor Builder, because a one-in-a-million draw gives a regular buyer no reason to come back sooner. A cashback is a strong Loader or Builder and a weak Breaker, because the reward only lands after the purchase the non-buyer has not made yet. The mechanic is not the strategy. The job is the strategy, and the mechanic is how you pay for it.
Once the job is settled, the friction question answers itself. If the job is data, you have earned the right to ask for more, because the reward is meant to be a fair trade for information. If the job is trial, every extra field on the form is a tax on the exact behaviour you are paying to create — a rough rule we use is that each additional field quietly costs you a slice of your entries, and the drop-off compounds. This is where a tool like Trudy, Trevor’s predictive promotional intelligence, earns its keep: it can look at thousands of past promotions and flag when the friction you have designed is out of step with the job you said you wanted.
What is the insult threshold in a promotion?
The insult threshold is the point where the reward is not worth the effort it takes to claim it. Ask someone to keep a receipt, scan a QR code, fill in a form and wait three weeks for a two-dollar cashback, and you have not run a promotion — you have run a test of their patience. Cross the threshold and entries do not just fall; the brand wears a small grudge that outlasts the campaign.
The threshold is not a fixed number, which is what makes it easy to trip over. It moves with the effort you are asking for. A low-effort entry can carry a modest reward and still feel fair. A high-effort claim — proof of purchase, multiple steps, a delay before payout — needs a reward big enough to justify the work, or the whole thing reads as mean. The trap is designing the effort and the reward separately: the operations team adds verification steps to control fraud, the finance team trims the prize to protect margin, and nobody notices that the two decisions, made in different meetings, have together pushed the offer over the line.
This is also where the One Job Rule and the insult threshold meet. If you have decided the job is data, you are by definition raising the effort, so the reward has to rise with it. A promotion that asks a lot and gives a little is not a frugal promotion. It is a promotion that will underperform and then get blamed on the category, the weather or the media plan — anything except the offer.
How do you test for this before launch?
You do not need a model to catch most of these problems — you need fifteen minutes and an honest answer to a few questions. The Shelf Truth calls it the Kill Sheet, and the first question is always the same: what is the one job? If three people in the room give three different answers, the promotion is not ready, and no prize budget will fix that. The next questions are whether the mechanic actually serves that job, and whether the reward clears the effort you are asking for.
Timing matters too. With the end of financial year landing in late June, a lot of Australian brands are about to push promotions into the busiest value-seeking window of the year. That is exactly when the temptation to make one campaign do everything is strongest, because the stakes feel higher. It is also when the discipline pays off most, because a crowded market rewards the offer that is clear about what it is for. Whatever mechanic you land on, it still has to be compliant — a game of chance can need a permit in New South Wales, the ACT, South Australia and the Northern Territory, and the rules are worth checking against the relevant state regulator and the Australian Consumer Law before anything goes live.
None of this is about doing less for the sake of it. It is about spending the same budget on one job done properly instead of five jobs done halfway. If you are pressure-testing a promotion before it launches and want a second read on whether the mechanic and the reward match the job, we are happy to talk it through.
