What I found
The line was not falling apart. Every spike in hours per unit lined up with a week we barely built anything. When a week ships 2 units, a normal load of fixed hours divides into a huge number. The metric was measuring volume, not how hard the crew worked.
What I built
A model that pairs weekly hours against units built for the full 2026 year to date, per assembly line and as a rollup, with a minimum-volume filter and a rolling-average option. The point was to stop anyone from quoting a three-unit week as if it were a trend.
How it works
Drag the minimum weekly volume. Weeks below the line drop out, and the headline range recomputes in place. Watch the band on the top chart collapse and the threshold line move across the units chart.
No minimum. Range about 42 to 545 hours per unit, roughly 13x, 30 of 30 weeks.
Raw, hours per unit runs from about 42 to 545 across the built weeks, a spread of roughly 13x. The spikes look alarming.
Hours per unit
Units built
Shown: total across all lines. The model also produces battery pack, EDU, general assembly, full vehicle, and HPC views, weekly, monthly, or quarterly.
View the weekly data
| Week ending | Hours per unit | Units built |
|---|---|---|
| Jan 18 | 49.7 | 29 |
| Jan 25 | 50.6 | 29 |
| Feb 1 | 62.2 | 21 |
| Feb 8 | 96.0 | 14 |
| Feb 15 | 42.4 | 34 |
| Feb 22 | 46.3 | 30 |
| Mar 1 | 89.2 | 13 |
| Mar 8 | 75.8 | 15 |
| Mar 15 | 50.7 | 23 |
| Mar 22 | 60.5 | 20 |
| Mar 29 | 74.0 | 15 |
| Apr 5 | 83.8 | 13 |
| Apr 12 | 212.2 | 5 |
| Apr 19 | 214.4 | 5 |
| Apr 26 | 184.8 | 5 |
| May 3 | 186.0 | 5 |
| May 10 | 100.6 | 9 |
| May 17 | 91.3 | 10 |
| May 24 | 79.1 | 10 |
| May 31 | 156.7 | 3 |
| Jun 7 | 122.4 | 7 |
| Jun 14 | 227.8 | 4 |
| Jun 21 | n/a | 0 |
| Jun 28 | 171.9 | 5 |
| Jul 5 | 167.4 | 5 |
| Jul 12 | 149.1 | 5 |
| Jul 19 | 195.7 | 5 |
| Jul 26 | 195.2 | 6 |
| Aug 2 | 545.2 | 2 |
| Aug 9 | 530.8 | 2 |
| Aug 16 | 80.4 | 18 |
Raw, hours per unit runs from about 42 to 545, a spread of roughly 13x. Set the minimum to 13 units and the range tightens to about 42 to 96, roughly 2x. Same crew, same plant. The swing was the denominator.
Impact
- The metric became something a director could act on, instead of a number that set off an alarm every low-volume week.
- It shipped with a rule attached: read it on a minimum volume or a rolling average before it goes in a deck.
- The same structure supports per-line views for battery pack, EDU, general assembly, full vehicle, and HPC, weekly, monthly, or quarterly.
The transferable lesson
A ratio is only as stable as its denominator. Before a per-unit metric goes near a meeting during a ramp, decide the minimum volume it is allowed to speak at. That one decision is the difference between a number people argue about and a number they can steer by.