The Night Shift · Department
code-results
Notes from building code-results — tying every deploy to the business metrics that moved after it.
7 essays filed here
- 01
Up in total, down in every part
You ship a change, and conversion climbs nine percent. Then someone splits the number by cohort and finds the truth: new users converted worse, returning users converted worse, every segment converted worse. The total rose anyway — because the release quietly changed who showed up, not how well the product worked. It's Simpson's paradox, and it's the trap a single headline metric is built to walk you into. code-results reads the number the only way that can't lie to you: split, and weighted by the mix that actually moved.
6 min read - 02
Two changes, one window
Ship one thing on a quiet afternoon and the number that moves after it is yours to read. Ship two things twenty minutes apart and the lift has no owner — it belongs to both changes and neither, and any clean split you draw between them is a number you made up. The honest move isn't to guess which deploy earned the win. It's to notice that, for now, the question can't be answered — and to say so out loud instead of picking a winner.
6 min read - 03
The change that moved nothing
Ship a change, watch the metric, and sometimes the line just… doesn't move. Most tools treat that as a non-event — no green arrow, nothing to celebrate, nothing to file. But a confirmed 'no effect' is a real result, and burying it is how a team pays twice: once to build the thing, and again to relearn that it did nothing. code-results stamps the flat line as a finding, not a gap.
6 min read - 04
The number you weren't watching
A change is a trade, not a gift. You ship to move one metric, you watch that metric, it moves, and you call it a win — while the number you never instrumented quietly moves the other way. The bill goes unread because it was never on the screen. code-results reads every deploy against the whole handful a business would notice, so the win and the cost arrive together, on the same board.
6 min read - 05
The result has a half-life
The answer to 'did it work?' isn't worth the same on Monday as it is three weeks later. Not because the number changes — because you do. The reason you shipped, the alternatives you weighed, the file you were nervous about: all of it decays out of memory on a curve. A verdict that arrives after the why is gone is a fact you can't act on. code-results is built to catch the answer while the reason is still lit.
6 min read - 06
The number moved. Was it you?
Sign-ups are up since you shipped. That feels like a win — but 'up' is a level, and a level is the one thing that can't tell you whether your change did anything. The real question is whether the line broke where your deploy landed, and that's a question of alignment, not analytics.
5 min read - 07
You shipped it. Did it work?
Most teams can tell you exactly what they shipped last quarter and almost nothing about whether it mattered. The feedback loop dies at the merge button — and that's the loop code-results is built to close.
5 min read