How we measure beer prices

Why this page exists

A price guide is worth exactly as much as the numbers in it. This page explains where each number comes from, how it was converted, how old it is and what can go wrong with it. It is written so you can judge whether to trust a number, not so we can look thorough.

Everything here describes how the system actually works today. If the method changes, this page changes with it.

Where the prices come from

We gather prices from four places, and they are not equally reliable:

• Our own crawler reads price lists and menus from venues' own websites. It is automatic, and it sometimes gets things wrong — see the section on confidence.
• OpenStreetMap tells us which venues exist, where they are and what kind of place they are. Not prices.
• Submissions from readers. Someone who stood at the bar and read the price off the board.
• Comparison against other price guides, in practice Pilsguiden, Ølindeksen and Pilsjakt. We use them to notice that our own number has gone stale, not as a source in themselves.

The half-litre price

One venue sells 0.33 litres, another 0.4 litres, a third 0.5 litres and a fourth a pint. The price on the sign cannot be compared directly between them, so everything is converted to what half a litre would cost: the price divided by the volume, multiplied by 0.5.

A 0.4 litre glass at 89 kroner therefore becomes 111 kroner per half litre. That is the figure used when venues are ranked against each other. The price you actually pay at the bar is always shown next to it, together with the size it applies to.

If the size is missing, we do not convert. A number without a volume is not a comparable price, and we do not pretend otherwise.

How sure we are of a number

Every price carries a confidence score. It is not an estimate of how cheap the venue is, but of how likely the number is to be correct right now.

The score is built from confirmations and disputes from readers, weighted by three things: how old the signal is, who it came from, and whether it arrived independently of the others. The weight halves every 45 days, so a confirmation from last year counts for little. Submissions from anonymous readers count for less than those from readers with a track record. Two people reporting the same price independently count for more than two reports from the same direction.

The starting point is deliberately sceptical: a single confirmation does not lift a price to full confidence. We also compute an uncertainty interval, so that "probably right" and "we honestly do not know" do not look the same.

How often the numbers update

Pages are rebuilt every 24 hours. A price sign that changes today therefore reaches this site within a day — provided we notice the change at all.

We do not always notice. The crawler only reads venues that publish their prices online. For the rest we depend on someone sending in an update. That is why the date a price was last confirmed is always shown on the venue's page: if it is old, treat the number accordingly.

Public registers

For venues where we have confirmed which company operates them, we pull two things from public sources.

The Norwegian company register (Enhetsregisteret, run by the Brønnøysund Register Centre) says whether the company is bankrupt, winding down, or whether the venue is registered as closed. A venue reported closed is marked as such, and the prices below it remain as history.

The Norwegian Food Safety Authority's smiley scheme gives the hygiene grade from the latest inspection. The scheme only covers venues that handle food, so a plain beer bar with no kitchen has no grade — and a missing grade means nothing more than that.

The link between a venue and a company registration number is confirmed by hand. We do not guess, because a wrong link would put a bankruptcy notice on an open bar, or another venue's hygiene grade on this one.

What we do not know

It is more honest to write the limitations down than to let you discover them yourself:

• Prices change without notice, and a venue may have raised its price the day after we read it.
• Happy hour varies more than ordinary prices, and we rarely catch exceptions for public holidays and events.
• A venue may serve several beers at several prices. We normally show the cheapest option on tap, not the whole menu.
• Automatic reading of menus sometimes fails. Among other things we have seen an alcohol percentage read as a price.
• Coverage is uneven between cities. Oslo is the best covered; other cities have fewer venues and older numbers.

Wrong numbers

If you find a price that is wrong, say so on the venue's own page. It takes seconds, and a dispute from someone who has just been there weighs heavily in the confidence score.

We would rather correct a number too early than too late. A price guide that is wrong about the price has no reason to exist.