There are an estimated 10,000 single-family offices globally managing an estimated $10 trillion in assets. US endowments and charitable foundations represent another $2 trillion. By most accounts, the "great wealth transfer" and other factors will cause these pools to grow rapidly in the coming decades. A majority of family office and institutional capital is “self-managed” by internal staff, but a fast-growing portion—about $4 trillion—is now managed by outsourced chief investment officer (OCIO) firms. The primary influence on portfolio management remains the Yale Model as described by David Swensen in his book Pioneering Portfolio Management. But that book was first published 25 years ago. Perhaps it is time for another leap forward. After a quarter-century, what does the evidence tell us about active versus passive investment strategies? Are there proven innovations in portfolio construction, manager selection, and/or product structure that should be adopted more widely?