Interlude II: One Number

The Founder slides a design mock across the table.

FOUNDER: The dashboard needs one number. Users want one number. Investors want one number.

INSTRUMENT: I can produce one number. To eleven decimal places, if you want it to look expensive.

FOUNDER: But.

INSTRUMENT: But you have read the strand. Which lie shall I choose for the number to tell? The mean, which no user is? Today’s point, which is mostly last night’s sleep? The accuracy, which cannot tell the hasty child from the careful one? The percentile, which is ordinal wearing a ratio’s suit?

FOUNDER: Users will not read an interval.

INSTRUMENT: Users read weather forecasts. Rain, seventy percent. They have been reading intervals since childhood; they have merely never been offered one about themselves, by a product with the spine to show its own uncertainty.

FOUNDER: And if the honest band is wide?

INSTRUMENT: Then the honest band is wide, and you have learned that your test is too short, which the strand priced for you to the second. The number was never for the user. The number was for the part of you that wanted to stop measuring.