The Tenner Test: Stress-Testing Big Decisions Without Wasting a Fortune

Most business decisions don't fail because the owner was stupid. They fail because nobody asked a simple question early enough: what would have to be true for this to work?

That question costs nothing. Yet plenty of SMEs will happily spend thousands on consultants, software or a new website before they've spent ten minutes poking at the assumptions underneath. So here's a cheap alternative. Call it the Tenner Test.

The tenner isn't a fee. It's a constraint. The idea is simple: before you commit real money to a decision, spend ten minutes and no more than £10 proving whether the thinking holds up. If it doesn't, you've saved yourself a fortune. If it does, you've got a clearer reason to press go.

Why another spreadsheet won't save you

Spreadsheets are brilliant at making weak assumptions look tidy. You can build a three-year forecast in an afternoon and convince yourself you've done rigorous analysis. But a forecast is only as good as the story underneath it. If the story is shaky, the spreadsheet just gives it a suit and a haircut.

The same goes for advice. Consultants aren't the enemy. Good ones can be genuinely useful. But another round of advice is often a way of delaying a decision you already suspect is wobbly. You don't need a 40-page deck to tell you that a new hire with no clear job to do might be a problem.

The Tenner Test is deliberately low-tech. It won't replace judgement. It won't make a bad idea good. What it will do is expose the gaps fast, while the stakes are still small.

The scorecard: five questions, two points each

Write the decision at the top of a piece of paper. Not a document, not a whiteboard, not a Notion page. Paper. Then score five questions from 0 to 2.

Give yourself 0 for 'no idea', 1 for 'we think so', and 2 for 'we can prove it'. Maximum score: 10.

1. What would have to be true for this to work?

This is the killer question. If you're putting prices up, what would have to be true about customer loyalty, competitor pricing and your own costs? If you're hiring a salesperson, what would have to be true about your pipeline, your onboarding and your ability to manage them? If you can't list the conditions, you're not ready.

Score 0 if the answer is a shrug. Score 1 if you've got a plausible theory. Score 2 only if you've got evidence, however small.

2. Can we reverse it cheaply?

Some decisions are easy to undo. A new social ad campaign can be switched off. A trial price change can be rolled back. A new hire is much harder. A product launch can leave you with stock and a bruised ego.

Score 2 if the decision is genuinely reversible within a month and without much cost. Score 1 if it's awkward but possible. Score 0 if you're basically jumping off a cliff and hoping the tide comes in.

3. Who has already voted with their wallet?

This is where most SME decisions get exposed. You don't need a focus group. You need a handful of customers who have already paid for something similar. Have they asked for this? Have they complained about the problem you're solving? Have they bought the prototype, the sample or the smaller version?

Score 2 if you've got paying customers or direct evidence. Score 1 if you've got friendly opinions. Score 0 if the only person who likes the idea is the person who thought of it.

4. What does it cost us in cash and attention?

The cash cost is usually obvious. The attention cost isn't. A new marketing channel doesn't just cost £500 a month; it costs the hours you'll spend learning it, checking it and worrying about it. That's time not spent on the thing that already works.

Score 2 if the cash and attention costs are clear and capped. Score 1 if you've got a rough idea. Score 0 if you're hoping it'll sort itself out.

5. What are we not doing instead?

Every yes is a no to something else. If you spend £10k on a rebrand, that's £10k not spent on a salesperson, stock, training or a rainy-day buffer. If you spend your Friday on a new website, that's Friday not spent ringing lapsed customers.

Score 2 if you can name the trade-off clearly. Score 1 if you've thought about it vaguely. Score 0 if you've convinced yourself this decision has no opportunity cost. It does.

How to run it in ten minutes

Get a coffee. Take a tenner. Sit somewhere without your laptop. Write the decision at the top of the page and answer the five questions. Be honest. A score of 1 is not the same as a score of 2.

Add up the total. Anything under 5 is a red flag. Between 5 and 7 is amber: proceed carefully, or find a cheaper way to test the idea first. Eight or above is green, but only if you haven't got a zero hiding in there. A single zero on reversibility or customer evidence can sink the whole thing.

The tenner comes in at the end. If you score below 8, don't spend the money yet. Spend the tenner on a customer phone call, a mystery shop of a competitor, or a coffee with someone who has already tried it. That's a much better use of a tenner than another round of internal debate.

The trap: fake precision

The scorecard is not a scientific instrument. It's a thinking aid. The moment you start treating the score as proof, you've missed the point. A 9 out of 10 doesn't mean the decision is right. It means you've got fewer obvious holes than usual.

The real value is in the conversation. If you run the test with a business partner or a manager, you'll quickly find out whether you're aligned. One person says reversibility is easy; the other says it's a nightmare. That disagreement is worth more than the score.

When to ignore it

Some decisions are so cheap and reversible that the test is overkill. Buying a new kettle for the office doesn't need a scorecard. Neither does testing a £20 boosted post.

But for anything that costs more than a few hundred quid, or anything that will take up headspace for months, the test is worth ten minutes. Pricing changes, new hires, big marketing spends, product launches, new premises, new software: those are exactly the decisions that deserve a bit of cheap scepticism.

The real point

Most SMEs don't have a thinking problem because they're short of intelligence. They have a thinking problem because they're short of time and surrounded by people selling solutions. The Tenner Test is a way of slowing down just enough to spot the weak assumption before it becomes an expensive lesson.

A tenner won't buy you certainty. It will buy you a better question. And that's usually worth more than another consultant's invoice.