Glossary
Keep in mind: the forecasts here are experimental. They are compared with a simple “no change” baseline and can be wrong.
Backtest
A test that replays the model over past data, day by day, using only what was known at that time, and then compares each forecast with what really happened. It shows how the model would have done before anyone relied on it. Good past results do not guarantee future results, and results for different countries are strongly related because they share the same oil-price path.
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Calibration and half-life
Calibration is the regular re-tuning of how fast the model assumes pump prices follow the market, using what really happened. A change is kept only if it does better on data it was not tuned on. The half-life is the time it takes for half of the expected move to happen: a half-life of 5 days means that after about 5 days half of the move is done. The speeds currently used are settings and assumptions, not measured facts, and they are being re-estimated; research so far suggests that adjustment is slower than the current settings assume.
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Crack spread
The gap between the price of refined fuel and the price of the crude oil it is made from. It is roughly what refining adds. When it is large, fuel costs more even if crude oil does not change.
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Crude oil and Brent
Crude oil is the raw oil pumped from the ground, before it is refined into fuel. Brent is the most widely quoted crude oil price, in US dollars per barrel (one barrel is about 159 litres). It reacts to world news within minutes and is the starting point of the forecast.
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Directional accuracy
How often the model got the direction right, up or down. Around 50% would be no better than guessing. Getting the direction right does not mean the amount was right.
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Equilibrium price
The model’s estimate of where the pump price is heading, based on today’s oil and fuel market prices, taxes and typical margins. It is a reference point, not a guaranteed destination: the long-run link between market and pump prices is only partly supported by the data, and margins drift. It is not an official price.
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Exchange rate and display currency
Oil is priced in US dollars but pumps sell in local currencies, so exchange rates matter. The site converts what you see using the European Central Bank (ECB) reference rates, which are published once per working day. The display currency is the one you choose in the header; euro is the default. Converted amounts are approximate and can differ from what you actually pay.
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Excise duty (fuel tax)
A tax the government charges per litre of fuel, whatever the price of the fuel. For example, if the duty is 0.50 euros per litre, it adds that amount to every litre. Rates differ by country and change when laws change, which the model cannot foresee.
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Expected move
How much the model expects the pump price to change in total, from today’s price to the equilibrium price, in money per litre. A plus sign means a rise and a minus sign means a fall. It is an estimate and can be wrong.
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Experimental
The forecasts here are a research experiment. On a strict out-of-sample test the currently published model is not better than “no change”. Use them to learn how fuel prices may move, not to make important decisions. Nothing here is financial advice.
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Forecast horizon
How many days ahead a forecast looks, from 1 to 14. A 7-day horizon is a guess about the price one week ahead. The further ahead the horizon, the less certain the forecast.
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Indicative range (confidence range)
A range around a forecast that shows how uncertain it is. It is indicative only, not a guaranteed 90% range: in out-of-sample tests the real price fell inside it less often than 9 times out of 10, so it is too narrow, and it is being recalibrated. Treat it as a rough guide, never as a guarantee.
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Lag (delay)
The time between a move in oil markets and the matching move at the pump. Typically this is about 5 to 15 days: roughly two thirds of a cost change reach the pump within a week and most of the rest within two. That is an average; single weeks can behave differently.
MAE (mean absolute error)
The average size of the forecast’s mistakes, ignoring whether it was too high or too low, measured per litre. For example, an MAE of 0.02 euros means the forecasts were off by about 2 cents per litre on average. Smaller is better; compare it with the MAE of “no change”.
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Margin
The part of the pump price that pays for distribution and the station’s business: transport, running costs and profit. It is not tax and not the cost of the fuel itself. The model uses typical values, so real margins can differ from day to day.
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Model
A set of simple rules and formulas that turns market prices, taxes and exchange rates into a forecast. It does not read news or social media. A model is a simplification of reality, so it can be wrong, especially when taxes, price caps or supply change suddenly.
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National average
The average pump price for a whole country, as published by its official source. A region is a smaller part of a country, such as a prefecture or a state. Where a country publishes prices per region, the Region selector lets you choose one. The price at your own station can differ from both.
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“No change” baseline
The simplest possible forecast: assume the pump price will still be the same as today. Any model has to beat it to be worth using. On this site, “no change” is the yardstick for every accuracy number.
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Pass-through
How a change in oil and fuel market prices is passed on to pump prices. It is not instant: stations sell fuel they bought earlier, so the pump price follows with a delay and in steps. The model describes this with a curve that moves the price part of the way toward the equilibrium price each day; the speed of that curve is a current setting that is being re-estimated.
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Plateau
The point when the price has absorbed about 95% of the expected move, so it has almost stopped changing. For example, “Plateau in 9 days” means the model expects most of the adjustment to be done in about nine days.
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Product prices
Refined fuels such as gasoline (petrol) and diesel are also traded on markets, in contracts called futures: agreements to buy a fuel at a set price on a later date. Their prices are closer to what stations pay than the crude oil price is, so the forecast looks at them as well.
Pump price
The price you pay for one litre of fuel at a filling station, taxes included. The site shows it per litre, in the country’s own currency or in the display currency you chose. For example, if a litre of unleaded costs 1.80 euros, the pump price is 1.80 euros per litre.
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Rockets and feathers
A pattern often reported in studies: pump prices rise quickly when costs go up but fall slowly when costs go down, like a rocket going up and a feather coming down. In this project’s data the pattern is not confirmed in general: it shows up only for diesel’s short-run pass-through, not for petrol or heating oil. The model uses separate speeds for rises and falls, but that is a modelling choice, not a proven result, and it is being re-examined.
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Shock
A sharp one-day move in the crude oil price, here a change of more than 3% once converted to a price per litre. A shock reaches pump prices only gradually, over roughly the next one to three weeks. For example, a big jump in crude oil today is usually not fully visible at the station for a week or two.
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Signal
A short hint based on the expected move. “Buy now” means the model expects the price to rise by a noticeable amount (about 3 euro cents per litre or more, in local currency) within a few days. “Wait” means it expects a fall of that size. “Neutral” means no meaningful move is expected. It is an experimental hint, not advice.
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Skill
A score that compares the model with the “no change” baseline. Positive means the forecasts were closer to the real price on average. Negative means assuming “no change” was closer. About zero means no real difference (within ±5% counts as a tie). Negative results are shown openly, not hidden. Counts such as “beat no change in X of Y series” are descriptive only: the series share the same oil-price path and calendar, so they are not independent evidence.
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VAT
Value-added tax, a percentage added to the price of goods. On fuel it is charged on top of the price that already includes excise duty, so it is part of what you pay at the pump. For example, at 20% VAT a fuel price of 1.00 before VAT becomes 1.20.
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Weekly and daily data
Not every country publishes pump prices every day. Some sources update daily, but many only once a week. With weekly data the newest price can be several days old, and the accuracy checks can only look one week ahead. The Forecast page shows the date of the price it used.
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See also: How it works · FAQ · Accuracy