How to A/B test posters in the street
A field guide to A/B test posters properly: two designs, unique QR codes per copy, fair placement, and reading scans per print instead of raw totals.
Grow a website with QR codes you can track
How to grow a website with QR codes on stickers, posters and packaging: unique codes per copy, scans per location, and a repoint trick that saves reprints.
Reading poster scan data without fooling yourself
Poster scan data is easy to misread. Which comparisons are fair, why totals lie, how big a sample you need, and what to do when two spots look identical.