Decisions and trade-offs

I spent four drafts on it. First a gauge centered on zero. Then the CEO’s objection, in Slack: a gauge that points at the average difference “will make it look like there is a difference even if there is not,” because the honest answer isn’t a number, it’s that zero sits inside the range. So: a gauge showing the band instead of the needle, a confidence score proportional to distance from zero, a range display fading toward zero, with my own doubt attached (“false impressions of distribution?”). Every intuitive display lied a little; every honest one needed the explanation back.

Ranges over point estimates

The constraint: One week, a scenario planner built on the model's projections, and a teammate's AI-generated mockup as the starting point. The planner was the head of product's idea, a project lead ran customer discovery with five pilot brands, and I was formally assigned the design.
The options: A single projected number, as the starting mockup rendered it; A range on the headline projection; The full statistical detail up front
The call: A projection rendered as one number reads as a promise the model can’t keep. When the actual lands outside it, the user doesn’t conclude the estimate had variance, they conclude the product lied. A range makes the model’s uncertainty part of the message instead of a footnote. I also rejected showing the full statistical detail up front, in favour of progressive disclosure, so the first read is simple and the proof is one layer down. The range only works paired with a stated posture, which is the argument I have made since March 2025: start from “this works and we’re confident in it; if you need proof, here it is.”
The cost: A range is harder to act on than a single number: a stakeholder who wants a target gets a span instead. I took that trade because the alternative degrades trust the first time reality disagrees.

the Campaign Planner MVP, shipped March 2026

Steppers over sliders

The constraint: The team had implicitly settled on sliders, because that is what the starting mockup produced, and the planner's layout was already crowded.
The options: Sliders, as the starting mockup produced them; Numeric inputs and steppers
The call: Sliders were the mockup’s idea, not a decision anyone had made. Numeric inputs and steppers made precise refinement easier while taking less room in an already crowded layout.
The cost: This one was advocacy rather than a trade: the team had settled on sliders by default, I argued for steppers, and steppers shipped.

the Campaign Planner MVP, shipped March 2026

The study that overturned my own assumption

The constraint: In April 2019, before there was any code, I catalogued migraine symptoms as design requirements and specced a dark interface in deep purple, on the reasoning that people with migraine may be particularly sensitive to light.
The options: Carry the 2019 assumption that brightness was the problem; Run a look-and-feel study and let the responses decide
The call: One response corrected the assumption I’d carried since 2019: “High contrast is akin to bright white for me.” The problem wasn’t brightness, it was contrast, and my 2019 spec hadn’t made the distinction.
The cost: The dark build didn’t land until February 2021, and on the brand navy rather than the purple I’d drawn.

a look-and-feel study of twelve responses from eleven people, October 2020