Your Screener Is Costing More Than You Think

A client tells you their target incidence is 30%. That sounds manageable. But the topline IR doesn't account for the screener. By the time you apply age qualification (pass rate: 85%), brand awareness (pass rate: 60%), purchase recency (pass rate: 45%), and category usage frequency (pass rate: 70%), your effective incidence rate is 30% × 85% × 60% × 45% × 70% = 4.9%.

That's not a 30% IR study. That's a 5% IR study, which means your sample costs just increased roughly 6x from what you originally budgeted.

Visualizing the funnel

The simulator lets you define each screener stage with a name and estimated pass rate. It renders a waterfall chart showing how many respondents survive each stage, starting from your initial invitation volume. The waterfall makes it viscerally clear where the biggest drops happen.

Nine times out of ten, the biggest kill is some behavioral criterion buried in question three of the screener. "Must have purchased the product in the last 30 days" sounds reasonable, but if only 12% of your target has done that, you just eliminated 88% of your qualified audience before they even start the survey.

The tool calculates the total number of invitations you'll need to send to hit your completion target, factoring in the cumulative screener attrition. This is the number operations actually needs. Not the topline IR. Not the sample size. The invitation volume.

Tech stack

React 18.2 + Babel CDN. The waterfall chart is built with plain SVG. The funnel math is multiplicative probabilities. Simple, but the visualization makes the abstract tangible in a way that spreadsheet math doesn't.