Smart-beta is one of the hottest trends in not just ETFs but all of investment management. Assets in the category have grown from $0 to almost $1 trillion in barely a decade. But what is it, exactly? 

On this week’s Trillions, Joel and Eric explore the mysteries of smart-beta. To some, it's all a mutation of passive indexing; to others, it's a better, cheaper version of active management. "Imagine R2D2 with the head of Peter Lynch," says Eric. 

And to help you understand how investors can use the products, Nir Kaissar, a Bloomberg Gadfly columnist and financial advisor, and Tom Psarofagis, an ETF analyst with Bloomberg Intelligence and former issuer of smart-beta ETFs, join to offer their perspectives.