&gt; The McKinsey study focuses on U.S. and Western European stock and bond markets and doesn’t take investments in emerging markets into account, largely because of a lack of reliable long-term data.<p>Wouldn&#x27;t that imply that their predicted returns are much lower than they&#x27;ll most likely be? Assuming that majority of growth over the next X years will come from emerging markets, if they&#x27;re leaving emerging markets out of the calculation then their estimates are going to be low.