How the index is made

Homivo reads the adverts of 51 estate agents across the Highlands and Islands every day: the text, the photographs, the floorplans, and the map pin. The index counts every advert that was for sale or under offer on the day the edition was built, at an asking price from £10,000 to £20 million. A home advertised by two agents is counted once.

The Highlands and Islands are the Highland, Moray, Argyll and Bute, Western Isles, Orkney, and Shetland council areas, and the islands of Arran and Cumbrae. Homes elsewhere in Scotland are left out, and so is a share of a home sold under a shared ownership scheme, because its price is not the price of the home.

Plots, sites, and land without a house are counted apart from homes, so they never pull a home price down. Homes are grouped by the council area of their postcode. A council area gets its own page when at least 30 homes are for sale there. Holiday-park lodges, caravans, and beach huts are counted, but they are not chosen as record breakers.

Prices are asking prices, not sale prices. In Scotland many homes sell for more than the offers-over figure, so a sale price is usually higher than the figures here.

A median or a percentage is printed only when it rests on at least 20 homes. Fewer than that and it is left blank rather than guessed. Counts are always printed.

A feature that comes from reading photographs or adverts is reported only when it has passed an accuracy check. A person checks a sample of the homes that were found to have it, against the photographs and the advert. The feature is reported when at least 10 have been checked and enough of them were right: 95% for views, water access, and planning permission, 90% for everything else.

A sea, loch, or mountain view counts when it can be seen from the home: from a window, a balcony, a terrace, or the garden, or when the advert says the home has it. An aerial photograph or a picture of the harbour in the town does not count. A view of the sea from more than 800 m inland needs more than a glimpse.

The price of a sea view is like for like. Homes are put in groups of one type (house, semi-detached or terraced, flat), one number of bedrooms, and one nearest town. A group counts when it has at least three homes with a sea view and three without. In each, the median asking price with a sea view is divided by the median without. The premium is the average of those ratios, weighted by how many sea-view homes each group holds, and is stated only over at least 10 groups and 50 sea-view homes.

Comparing by bedrooms alone sets a flat in a cheap coastal town against a house in a dear inland one. Comparing by council area hides that most sea views are in the cheaper towns. The nearest town keeps like next to like.

The town table counts homes whose nearest town is within 30 minutes' drive. A town is listed when it has at least 20 homes for sale and 5 with a sea view. The cheapest sea view leaves out holiday-park lodges, caravans, and homes under £25,000.

A home is by the sea, a loch, or a river when its map pin is accurate and within 100 m of the mapped coastline, a loch, or a river. A pin placed only on the town is not used.

Land reaching the water is stricter. The advert has to say that the home's own land reaches the shore, the beach, or the bank, the pin has to be within 250 m of the water, and no public road or railway may lie between. Fishing rights, or a path to the shore, are not enough.

Drive times to the nearest town, primary school, and railway station are by road, worked out on the OpenStreetMap road network. The five nearest in a straight line are each routed, and the shortest drive is kept. A station route more than four times the straight-line distance is treated as unknown rather than counted.

Acreage is read from the advert. A figure far larger than the asking price could buy, such as a share of common grazing, is left out, and so is a home whose advert gives no acreage.

A home is in a Gaelic-medium catchment when its pin falls inside the catchment of a Gaelic-medium primary school, as published by the council. The figure is given for Highland, where those catchments are published.

A new edition is built each quarter. Once published it is frozen, so a figure quoted from it never changes. The newest edition is always at homivo.co.uk/reports/highlands-property-index, and each edition keeps its own address for citation.

The figures, charts, and data download are free to use under the Creative Commons Attribution 4.0 licence. Please credit "Homivo, Highlands and Islands Property Index" and link to the page you used.

This edition reads the adverts of these agents:

• AB & S Estate Agents
• Aberdeen & Northern Estates
• Aranci & Firth
• Arthur & Carmichael
• Bell Ingram
• Belvoir
• Caledonia Estate Agency
• CCL Property
• Cluny Estate Agents
• Clyde Property
• Corrigall Black
• Dawsons
• Dunoon Property
• e2w property services
• Fiuran Property
• Galbraith
• Grampian Property Centre
• Grant Smith Law Practice
• Grigor & Young
• Hamish Homes
• Harper Macleod
• Highland Homes
• Highland Property Services
• Home Sweet Home
• Innes & Mackay
• Knight Frank
• Low & Partners
• MacKenzie & Cormack
• Macleod & MacCallum
• MacPhee & Partners
• Masson Cairns
• McEwan Fraser Legal
• McIntyre & Co
• Munro & Noble
• Paul Coutts Estate Agency
• Pollard Property
• Purplebricks
• R & R Urquhart
• RE/MAX Skye
• Robb Residential
• Savills
• Smart Moves
• South Forrest
• Stewart & Watson
• Strutt & Parker
• Tailormade Moves
• The Estates Office
• Thorntons Property Services
• Waterside Property
• Your Move
• Yvonne Fitzgerald Properties