Knurd skrev: med hänvisning till institutet PEW.
Menas det här amerikanska PEW?
http://www.pewforum.org/2012/12/18/glob ... cape-exec/http://features.pewforum.org/grl/population-number.phphttp://www.pewforum.org/2012/12/18/glob ... thodology/Jag har bara snabbläst det, men deras metod är att leta upp officiell statistik på hur folk identifierar sig och sen analysera dem, och i annat fall göra en godtycklig bedömning utifrån ursprung.
PEW skrev:Data Collection and Documentation
Pew Forum researchers acquired and analyzed religious composition information from about 2,500 data sources, including censuses, demographic surveys, general population surveys and other studies – the largest project of its kind to date. Censuses were the primary source for Pew Forum religious composition estimates in 90 countries, which together cover 45% of all people in the world.17 Large-scale demographic surveys were the primary sources for an additional 43 countries, representing 12% of the global population. General population surveys were the primary source of data for an additional 42 countries, representing 37% of the global population.
Together, censuses or surveys provided estimates for 175 countries representing 95% of the world’s population. In the remaining 57 countries, representing 5% of the world’s population, the primary sources for the religious-composition estimates include population registers and institutional membership statistics reported in the World Religion Database and other sources. A list of the primary sources used to estimate the overall religious composition of each country is provided in Appendix B.
Censuses and nationally representative surveys can provide valid and reliable measures of religious landscapes when they are conducted following the best practices of social science research. Valid measurement in censuses and surveys also requires that respondents are free to provide information without fear of negative governmental or social consequences. However, variation in methods among censuses and surveys (including sampling, question wording, response categories and period of data collection) can lead to variation in results. Social, cultural or political factors also may affect how answers to census and survey questions are provided and recorded.
Verkar lite vanskligt. Alla skall passa in i mallarna utom de som uttryckligen uppgett "unaffiliated". Sverige har alltså ca 6,3 miljoner kristna, även om detta knappast är andelen religiöst kristna.