Have Alternative Investments Helped Investment Outcomes?

NACUBO just released its annual survey of the investment outcomes of the portfolios of nearly 700 college and university endowments in the US. If one compares the investment results of these endowments to simple stock/bond portfolios over the past two decades, it is hard to detect that any advantage has been obtained, on average, from having about 1/3 of investments in less liquid private investments and hedge funds. These portfolios would have had better outcomes if the illiquid investments had been replaced with similar liquid investments.