In a recent lecture I pointed out that lower correlation translates into greater diversification benefit, i.e. portfolio risk reduction. I also mentioned that international diversification may help. How much help depends on how low the rho (correlation). Here’s an article with an interactive map to see correlations between the US market and those of countries around he world.

http://www.cnbc.com/2016/02/12/the-majority-of-international-markets-are-down.html