He is the lead portfolio manager for the active emerging market large and small cap portfolios and assists in the management of the frontier markets product. (ssgafunds.com)
I suspect what's at least as important here is that the factors aren't strongly correlated with a large cap portfolio. (monevator.com)
Whether you include small / value etc should really depend on your own view of how much these are likely to outperform the simple global market cap portfolio over the term of your retirement. (monevator.com)