Methodology

How We Score Safety

Every score on SafetyScorer answers one question: compared with the alternatives, how likely is this to hurt you? A score of 100 means the risk is as low as anything in its category gets. A score near 0 means a serious, well-documented risk. The scale is the same for an airliner, a city and a supplement, so an A always means the same thing.

The grades

Grade	Score	What it means
A	85 to 100	Excellent. The risk is very low and well understood.
B	70 to 84	Good. Some known risks, mostly under control.
C	55 to 69	Fair. Real risks that you should plan for.
D	40 to 54	Weak. Serious risks for many people.
F	0 to 39	Poor. High risk, or a record of serious harm.

Aircraft: calculated from data

Aircraft scores are not written by hand. We take every fatal accident in the Aviation Safety Network database, keep the passenger flights, weigh each accident by the share of people on board who died, and divide by an estimate of how many flights the type has made. Types with few flights are pulled toward the record of their technology generation until their own record is long enough to speak for itself. Types whose scores are within 1 point share a rank, because a smaller gap is within the uncertainty of the data. The full method, with the formula and a worked example, is on the aircraft methodology page.

Everything else: fixed factors and weights

For airlines, countries, cities, apps, medications, supplements, crypto exchanges, banks and activities, each category has a short list of factors with fixed weights. A country, for example, is scored on violent crime, conflict and terrorism, road safety, health risks, natural hazards and petty crime. Each factor gets a score from 0 to 100 against a written rubric with numeric thresholds, such as Homicide rateThe number of people killed on purpose each year for every 100,000 residents. It is the most comparable crime figure between countries.More in the glossary people. The overall score is the weighted average. Every category page links to its factors and rubrics, for example the countries methodology.

Countries have one extra rule: the overall score can never be more than the conflict and terrorism score plus 35. A country at war can still have normal crime, roads and hospitals, and a plain average would let those lift it to a middling score. With the cap, a country whose conflict score is 3 can score at most 38, whatever its other factors. For most countries the weighted average is already below the cap, so it changes nothing. Pages where the cap applies say so in "How we scored it".

We do not adjust the overall score by feel. If a result looks wrong, we check the factor scores and the data behind them.

Confidence

Each score carries a confidence label. High means the data is recent, official and plentiful. Medium means some figures are estimates or a few years old. Low means the record is thin: a new aircraft type with few flights, or a country that publishes little crime data. A low-confidence score can move a lot when new data arrives.

Sources and updates

Every page lists the sources it uses, with links, and shows the date it was last checked. We prefer primary sources: investigation reports, regulator decisions, official statistics, drug labels and company filings. News reports are used for recent events, and we say so.

What a score cannot tell you

A score describes typical risk, not your trip, your dose or your account. Your own choices often matter more than the average: a seat belt on a long flight, the neighbourhood you stay in, the other medicines you take. Scores are information, not medical, financial or travel advice. When new data changes a score, we update the page and its date.