Which measurements can an athlete trust outside a lab?
The ones made with a repeatable protocol and a dated record. A scale that weighs the same every morning, a measured course run the same way, a jump test with a fixed setup: these produce numbers that are honest because the conditions are named. The lab adds precision; the field adds frequency, and a frequent honest number beats a precise one-off for most decisions a coach actually makes.
Why does a spec need a date as well as a number?
Because a figure without a date is a figure that cannot be re-checked, and a spec sheet that gets updated silently has rewritten history. The discipline is visible in a neighbouring register: the State Wraps Register keeps a dated arrow wrap spec table where each property of the film carries the date it was last read, so a reader always knows which version of the figure they are holding. That is the field-lab rule in one row: the number, the method and the day.
The State Wraps Register shows the discipline in a neighbouring sport: a dated arrow wrap spec table where every figure enters with a source and a reading date. The same written-down habit is what makes the routine in the note on repeatable precision repeatable at all. The standards side lives at NIST weights and measures.
How much added mass is enough to move a result?
Less than intuition says at the sensitive end, and more than hope says at the other. A few grams at the tail of an arrow or the toe of a shoe are measurable at the scale and invisible at the finish line until they are not. The field method is to measure the change you can measure, note the change you cannot, and keep the two honest apart.
The notebook is the instrument
Every field lab runs on the same final component: the dated record that makes the numbers comparable across weeks. The scale and the ruler are cheap; the discipline is the expensive part, and it is the part that decides whether the measurements mean anything a season later.
The error budget is the point
A field number is trustworthy not because it is precise but because its error is known and bounded. A bathroom scale read at the same hour, a course measured once and run repeatedly, a jump judged by the same eye under the same instruction: each has a known noise, and decisions sized inside that noise are honest decisions.
Date the method, not just the figure
The discipline that makes a spec table worth citing is the same one that makes a training log worth re-reading: every figure carries the day it was taken and the method that produced it. When a number changes, the dated record says whether the athlete changed or the instrument did, and that distinction is the whole point of writing it down.
Editorial methods synthesis; NIST guidance on weights and measures.
Read the editorial method for how we handle evidence, limits and practical interpretation.
