Homogeneous polities have less crime, less civil war, and more altruism.
https://link.springer.com/article/10.1007/s10464-013-9608-0
Diversity increases psychotic experiences and social adversity.
http://bjp.rcpsych.org/content/201/4/282.full
Borders, not multiculturalism, reduce intergroup violence.
http://arxiv.org/abs/1110.1409
Assimilation into a host culture improves well-being.
(aitch) (tee) (tee) (pee) (colon) (slash) (slash) (double-u) (double-u) (double-u) (dot) ncbi (dot) nlm (dot) nih (dot) gov (slash) pubmed (slash) 24364853
Immigration to the United States has increased income inequality.
http://spa.sagepub.com/content/early/2015/09/21/1532440015603814.abstractEthnic diversity among members of the same race reduces infrastructure quality, charity, and loan repayment.
(aitch) (tee) (tee) (pee) (colon) (slash) (slash) onlinelibrary (dot) wiley (dot) (cee) (o) (em) (slash) doi (slash) 10 (dot) 1111 (slash) j (dot) 1467-9477 (dot) 2007 (dot) 00176 (dot) x (slash) abstract
Immigration reduces the academic performance of native schoolchildren.
http://wol.iza.org/articles/immigrants-in-classroom-and-effects-on-native-children
Ethnic diversity causally decreases social cohesion.
http://esr.oxfordjournals.org/content/early/2015/08/20/esr.jcv081.full
Ethnically homogeneous neighborhoods are beneficial for health.
https://www.mailman.columbia.edu/public-health-now/news/living-ethnically-homogenous-area-boosts-health-minority-seniors
Ethnic diversity reduces social trust.
http://www.nber.org/papers/w5677
Ethnic homogeneity correlates with strong democracy.
https://www.washingtonpost.com/news/worldviews/wp/2013/05/16/a-revealing-map-of-the-worlds-most-and-least-ethnically-diverse-countries/
Ethnic diversity reduces concern for the environment.
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