The Offset Card, and Why We Print One Instead of Claiming Accuracy

The offset card started as an internal document. For the first two seasons we kept the corrections to ourselves and simply applied them quietly before handing over a recommendation. A client asked, not unreasonably, why we got to know something about our own equipment that he did not. We printed the card the next week and have handed one out with every full-swing session since.

What Actually Prints on the Card

A table, one row per club category, split by clubhead speed band where the sample supports it. Each row states a direction and a size: the driver reads long, the bay overstates it by a specific number of yards for your speed band. The pitching wedge reads short. A mid iron is close enough that the row says so plainly rather than printing a false decimal of precision.

Nothing on the card is described as accurate. Every row is described as a measured difference between two things: what our screen said in the bay, and what the same swing produced on grass during a paired block. That framing is deliberate. “Accurate” implies we know the true answer. “Measured difference” only claims we compared two things honestly.

Where the Numbers Come From

Every figure traces back to a paired block: the same golfer, the same ball, the same club, hit indoors and then on turf within about a week, both sets scored the same way and dropped into the same row of a spreadsheet. I keep that spreadsheet and it now runs past four hundred paired entries across nine audit seasons.

Rows with fewer pairs behind them are marked with lower confidence rather than hidden. A four iron offset is built from fewer entries than a seven iron, because fewer of our clients still carry a four iron, and the card says so. Confidence on the card reflects how many pairs stand behind a number, not how convenient the number would be to print.

Four Things the Card Is Explicit About Not Covering

1. Rollout. Total distance depends on ground firmness we cannot observe from a bay in Eugene, so the card only ever speaks to carry.
2. Wind. The correction is derived in still conditions on both sides of the comparison. Nothing on the card adjusts for a crosswind.
3. Altitude and air outside the Willamette Valley. A figure built here is built for this elevation and this air. It is not portable to a trip to Bend or Bandon.
4. Anything below a full swing. Chips, pitches and putts are not on the card at all. The paired-block method depends on a repeatable full-swing strike, and a half-swing does not give us that.

A correction table that claimed to handle all four of those would not be a correction table. It would be a marketing document wearing a spreadsheet's clothes, and we would rather leave rows off the card than print a number we cannot stand behind.

What the Card Is Actually For

Not to make the bay sound better. The point of the card is narrower and more useful than that: it lets a number generated in this building travel with you to an actual golf course and still mean something. A six iron that reads a hundred and sixty-six yards in Bay One is not a hundred and sixty-six yards at Riverridge, but with the card in hand you know roughly what it becomes, and your gapping chart can be built on the corrected figure rather than the raw one.

Clients occasionally ask why we do not just skip the bay and re-fit everyone outdoors once the weather turns. The short answer is that a repeatable comparison needs a room that holds still, and Eugene does not offer that reliably for two-thirds of the year. The card is how we get the benefit of a controlled room without pretending the room is a golf course.

Teddy Lindqvist derives every figure that reaches an offset card at Dialed In Lab in Eugene, Oregon.