Vouchers, guest lists and ratings

Three code types that ask the scanner to do something, and count that they did.

A voucher

Set the offer, optionally a code for the till, and how many there are altogether. Scanning shows the offer; a member of staff marks it used.

**Put a password on the code.** Marking a voucher used sits behind it, so it is the person behind the counter who does it and not the customer. Without one, anybody can mark their own voucher used the moment they look at it — and every figure after that means nothing. The page says so while there is no password, which is the moment to fix it rather than a month later.

The two numbers to read are issued and redeemed, and the ratio between them. Five hundred scans and four redemptions is a bad offer. Forty scans and thirty redemptions is a good offer nobody saw. Neither number on its own tells those apart.

A guest list

Somebody scans, types their name, and is checked in. The useful output is the arrival times rather than the list — that is the question anybody running a door actually has.

A rating

Five stars, one tap, recorded. There is no form and no email box, and the comment box only appears after the tap — so a rating counts whether or not anybody writes anything.

That is the whole design. Every tap somebody has to make after the first is a share of the answers lost, and on a table card the first tap is most of what anybody will give you.

No average is shown until at least five people have answered. Below that a single five-star tap reads as a perfect score and a single one-star as a catastrophe, and both are one person having a morning.