The Math Audit: How to Verify Any Sales Candidate's Performance in Less Than Five Minutes

I was sitting in on a Zoom interview with a founder last week. The candidate was impressive, confident, curious, a lifelong athlete, and exactly the kind of person you want in the room. He'd even led his team in sales for two years running. About twenty minutes in, the CEO slacked me.

"This might be our guy."

Then we started talking numbers. He told us he hit 118% of quota last year on a $600,000 target. When we asked his average deal size, he said it was $3,000 ARR with a fifteen-day sales cycle. A few minutes later, we asked how many deals he closed per month, and he said fifteen.

The CEO moved on to another topic.

I stayed with the numbers: 15 deals a month, $3,000 ARR, twelve months.

15 x 12 = 180 deals.

180 x $3,000 = $540,000.

A few minutes later, I asked how much he actually sold last year.

$625,000.

I looked at my other screen where the CEO was already typing out the math. The numbers didn't match, not even close. We weren't trying to catch him; we were just verifying. But the rest of the interview went downhill from there.

This Happens More Than You Think

Most interviews stop after quota attainment. People hear a percentage and they never verify the story behind it.

Candidates naturally remember their best stretch, like their best quarter or the month everything clicked. They're rarely remembering the full year. Because most interviewers never do the actual math, those numbers never get pressure tested.

That's what the Math Audit is. It's not an interrogation. It's a simple verification process that takes less than five minutes and tells you more about a candidate than almost any other question you can ask.

When a candidate throws out numbers throughout an interview, whether it is quota, attainment, deal size, sales cycle, deals closed, or total revenue, they need to tell a consistent story. When they don't, something needs explaining.

Here is how you run it conversationally in real time.

First, establish the baseline by asking for their quota and attainment. Let them give you the percentage, write it down, don't react, and just move on. A few minutes later, get the components. Casually ask for their average deal size and the average number of deals they close per month. Keep it relaxed, because you’re not auditing yet, you're just gathering information.

Then, do the quick math on your notepad:

Deals per month x 12 = deals per year.

Deals per year x average deal size = implied annual revenue.

Compare that number to what their quota attainment actually suggests. If quota was $600,000 and they said 118%, their implied revenue should be around $708,000. If your math gets you to $540,000, the numbers don't match.

That’s when you hit them with the question most interviewers never think to ask: "How much did you actually sell last year?" Not the attainment, not the percentage. The actual dollar amount of total revenue closed. That is the question that closes the loop.

If the numbers don't align, just point out the gap factually and without accusation. You can just say, "Help me understand something. Based on your deal size and monthly close rate, the math gets me to about $540,000. But you mentioned 118% of a $600,000 quota. Can you walk me through that?"

What happens next is usually the most revealing part of the entire interview.

Strong candidates usually have a clear explanation. Maybe the territory changed mid-year, the quota was adjusted, or deal sizes varied significantly. They can walk you through it without hesitation because they lived inside those numbers every day.

Weak candidates get vague, get defensive, or start recalculating on the fly.

What the Math Audit Actually Reveals

The goal isn't to catch someone in a lie. It's to understand their relationship with their own performance.

A-Players know their numbers inside and out. Not because they memorized them for the interview, but because they lived them. Quota attainment wasn't a statistic to them; it was the scoreboard they checked every single morning.

When a candidate can't walk you through their own numbers clearly, it usually points to a few specific things. They might be approximating a result they never truly owned, they could be remembering a strong stretch rather than the full picture, or they simply never faced the kind of accountability that required them to know.

None of those things automatically disqualifies a candidate, but all of them are worth understanding deeply before you extend an offer.

One More Thing

The Math Audit works in reverse, too.

When a candidate's numbers add up perfectly and they can explain every moving part without hesitation, that's a signal worth paying attention to. Not because the math proves they're a superstar, but because knowing your numbers at that level of detail proves you ran your territory like a business.

The math tells you the story. Your job is just to math the math.