According to international law, everyone has the right to freedom from arrest or detention for: reasons not established by law; inability to fulfil a contractual obligation; thoughts, beliefs, conscience, or religion; opinions or their peaceful expression; participation in peaceful assembly; peaceful association with others, including trade union membership; or identity, including 'race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status' (ICCPR, Part II, Article 2; Part III, Articles 9, 11, 18 19, 21, 22 & 26).
We measure all civil and political rights using a survey of in-country human rights experts. We ask questions about the frequency of violations of each right, then combine the answers with a statistical model that means we can compare responses across countries, and over time.
We then show the results as an estimated score out of 10, within an uncertainty band.
We also ask the in-country experts about who is at particular risk of human rights abuses. We show information based on their responses on the 'People at risk' tab on the country pages.
The short answer is that this sometimes happens when we convert our statistical calculations into scores from 0 to 10, and it doesn’t mean anything special.
The more detailed answer is that when we calculate our civil and political rights scores, the results could theoretically take on any value. Because there are not real limits on the scores that come out of our model, we sometimes end up with uncertainty bands that range beyond 10 or below 0. We still present those bands completely – and don’t just cut them off at 0 or 10 – to accurately show our level of certainty in the country's score.