# How we choose what is featured

**Version 2, 2026-09-20**

Every list on this site that says "featured" is put in order by one rule, written here in plain words and read by the site itself each time this page is served. The home page's headline and grid, the savings rails on the drinks and beauty pages and on each category's page, brand pages, the best-value block on an airport page and the full list sorted by "Featured" all run the same order. An admin's pick comes first, then the picture and how good its source is, then a competition award, then how the saving stands as a percentage and in dollars. The first eight places carry the mix; after that the saving alone decides.

## What "featured" means

A featured product variant is a real saving a traveller can act on: the same bottle or item, priced at two or more of our airports, in stock somewhere, its size known, its prices recent. "Featured" is not a paid placement and not a retailer's promotion. Nothing on this site is featured because a shop or a brand asked for it; the only person who can move a product variant up a list is an admin of this site, and that choice is recorded (see What an admin's pick does).

## What a comparison is

A comparison is one product variant priced at two or more of our airports. The saving is the gap between the highest and the lowest of those prices, in US dollars and as a share of the highest. An online catalogue we read identifies a product variant (its barcode, its size, its brand) but never takes part in a comparison and never confirms a gap: a price on a shelf at an airport is what a traveller can compare, and only airports count.

## A price is what a shop showed on a date

A price on this site is an observation: what a shop's public listing showed on a date, in the shop's currency, converted to US dollars at that day's rate so shops can be set side by side. It is never "the price". Duty-free pricing varies by destination, loyalty tier and traveller, and every price we show carries its date. A comparison whose newest price is older than `STALE_DAYS = 14` days stays on its own page, dated, but leaves every featured list until a fresh price arrives; one whose oldest price is past `EXPIRED_AFTER_DAYS = 60` days does the same, so a shop we can no longer read cannot hold a frozen saving on a rail.

## The factors, in order

The site's owner set the order: an admin's pick, then the picture, then an award, then the saving as a percentage, then the saving in dollars.

- **An admin's pick** leads every list the product variant is already a comparison in. It never adds a product variant that has no saving, and it never labels one.
- **The picture, and how good its source is.** A picture is scored on a ladder from 0 to 6: no picture; a brand's mark, a product line's picture or a product variant's own picture from a public source; then the same three levels supplied through this site's admin (the brand's own or the client's), which rank above anything fetched. Each rung adds one fixed step, so a supplied picture of the product variant itself adds six steps and a public product line picture adds two. A brand's mark counts as a picture on the ladder, but only a picture of the bottle or item itself (a product line's or a product variant's) can make a product variant the page's headline.
- **An award** from the competition network adds a fixed bonus, counted only when the saving stands at least half as well as the best in its pool. No winner is featured on a poor saving.
- **Where the saving stands.** Each saving is placed twice, by its percentage and by its dollars: its standing is the share of the other savings in the same pool that it beats, so one extreme bottle cannot flatten every other card. The two standings are averaged, half and half.

The picture and award bonuses count in full for the first eight places, fade over the next sixteen and are gone by place twenty-four; past that only the saving decides.

| What counts | How much | In the code |
|---|---|---|
| The rules version, equal to this page's version line | 2 | `VERSION = 2` |
| The smallest gap that is a saving at all, in US dollars | half a dollar | `REAL_SAVING_USD = 0.50` |
| The percentage standing's share of the saving score | half | `PCT_WEIGHT = 0.5` |
| The dollar standing's share of the saving score | half | `USD_WEIGHT = 0.5` |
| The bonus for each rung of the picture ladder | 0.06 per rung, 0.36 at the top | `PICTURE_STEP = 0.06` |
| The rung an older record's plain "has a picture" flag reads as | a public product variant picture | `LEGACY_PHOTO_TIER = 3` |
| The bonus for a competition award | 0.10 | `AWARD_BONUS = 0.10` |
| How well a winner's saving must stand, against the pool's best, for its award to count | half | `AWARD_FLOOR = 0.5` |
| Days since the newest price after which a comparison leaves the lists | fourteen | `STALE_DAYS = 14` |
| Days since the oldest price after which a comparison leaves the lists | sixty | `EXPIRED_AFTER_DAYS = 60` |
| A gap this many times the lower price is held back until a third airport confirms it | three times | `MAX_UNCORROBORATED_RATIO = 3.0` |
| The airports it takes to confirm such a gap | three | `CORROBORATION_SHOPS = 3` |
| A headline candidate is dwarfed by a card saving this many times its dollars | twice | `HEADLINE_DWARF = 2.0` |
| How many cards may dwarf the headline before it loses the place | one | `HEADLINE_OUTLIERS = 1` |
| Product variants of one brand in the first eight | one | `MAX_PER_BRAND_FIRST = 1` |
| Product variants of one category in the first eight | three | `MAX_PER_CATEGORY_FIRST = 3` |
| Travel exclusives in the first eight | one | `MAX_EXCLUSIVE_FIRST = 1` |
| The places that carry the mix | eight | `FIRST = 8` |
| The places the two best savings must appear within | four | `FIRST_MIX = 4` |
| The place by which the picture and award bonuses have faded to nothing | twenty-four | `DECAY_END = 24` |
| How far apart the two standings must be before a saving is called percent-led or dollar-led, in our own checks | fifteen points | `LEAD_MARGIN = 0.15` |
| How many of the first eight we expect to carry a picture, in our own checks | six, or every pictured product variant the pool holds | `PICTURED_TARGET = 6` |
| The most award winners we expect in the first eight, in our own checks | four | `AWARDS_TARGET_MAX = 4` |

## The first eight, and after

Only comparisons that pass the guards below are in the running, and they compete within the list they are on: the whole catalogue on the home page, one category on its page, one brand on its own. The first eight places are filled in this order: an admin's picks; then the two best savings in the pool (the largest in dollars and the largest as a percentage), each within the first four places; then the highest scores that keep the mix, with no more than one product variant per brand, three per category and one travel exclusive among the eight. Where a list cannot honour a cap (a brand page holds one brand; a category page holds one category) that cap is off, and where nothing left honours the caps they relax rather than leave a rail short. A rail runs short only for lack of eligible comparisons; it is never padded with a stale, sold-out or unconfirmed one. From place nine the bonuses fade until, at twenty-four, the saving alone decides. The card drawn large at the top of the home page is the admin's first pick if there is one; else the best-placed award winner with a picture of the bottle that no more than one other card dwarfs in dollars; else the first place.

## The guards

A comparison is left off every featured list, and stays on its own page with its dates, when any of these holds: it is priced at fewer than two of our airports; its saving is half a dollar or less; no shop shows it in stock; its size is unknown (an unknown size is as likely two sizes folded together as one); its newest price is more than fourteen days old, or the date is unknown; its oldest price is more than sixty days old; or the gap is more than three times the lower price and only two airports show it, which is as likely a pricing error as a bargain until a third airport confirms it.

## What an admin's pick does

An admin of this site can pin a product line or a product variant. A pinned product variant leads every list it is already a comparison in; a pinned product line lifts its one best product variant. A pin orders: it never admits a product variant with no saving to a featured list (one priced at a single airport heads only the un-compared tail of the full list), and it never labels the card. Every pin is a recorded decision with who made it and when, and undoing it releases the pin; a rule never pins anything.

## What is never done

No retailer's photograph is copied and no retailer's marketing copy is reproduced: a picture on this site is the brand's, the client's or openly licensed, and says so. We never log in to a shop, never create an account and never accept a shop's terms. No placement is sold: a sponsor's tile is marked as one and never takes a featured place. "Duty free" names the shopping channel, not a price; we say which airport showed the lowest price of those we compared, dated, and never claim a price is the lowest anywhere.