Intercommunal tension escalates once a minority exceeds roughly ten percent

Evidence

Research by Robert Putnam has confirmed the seemingly self-evident logic that the greater the ethnic diversity in a community, the lower the degree of trust between members. Other scholars have noted that intercommunal tensions tend to present problems when the minority group breaks the level of ten percent of the general population. At that point, fears among the majority population tend to increase. — Michael A. Reynolds and Thomas D. Grant, The Future of Europe and Its Muslims, 264

Categorization

• QUESTION: Is the ten percent threshold a robust cross-cultural regularity or an artifact of a handful of cases? Worth chasing whether anybody has actually tested it comparatively.
• XREF: Connects to Putnam’s social capital work on bonding versus bridging ties — diversity lowering in-group trust while raising out-group tolerance.