Christians in countries like these are often the targets of Muslim extremists because their faith is in direct opposition to their cause. You can learn more about each country at https://www.opendoorsusa.org/christian-persecution/world-watch-list/.
The methodology is based off of an expert questionnaire. A full explanation of the methodology is available on the website.
It is illegal to be a Christian in North Korea and Christians are often sent to labor camps or are killed if they are discovered. The conditions in this country have remained the worst in the world for Christians for the past 13 years.
There are more than 65 countries where Christians are persecuted. These are just the top 50.
There are countries on the list which have a rather large Christian population and remain on the list for numerous reasons. In countries like Colombia, Christians face persecution from rebel groups in certain parts of the country. While non-Christians also experience violence from these groups, Christian leaders are specifically targeted because many people have left the rebel groups after coming to Christ. The church is often seen as a threat by these groups because of this and is often attacked.
Not always. Countries like China have areas where there is virtually no persecution and areas where there is persecution. However, in some countries like North Korea, there is persecution throughout the country.
A Muslim Background Believer (MBB) is a Christian who comes from a Muslim Background. Often these Christians face persecution from Muslim family members, who observe a strict form of Islam.