Maybe not always. At least that was the upshot of a debate between Cliff Asness of AQR and Rob Arnott of Research Affiliates, panelists at the recent Morningstar conference in Chicago. Although they debated various topics, they seemed to agree that value stocks deserve attention when they’re cheap. According to Asness, founder and managing principal at AQR, “Timing the market is hard and we call it a sin, but we recommend that investors sin a little.”

The panelists discussed the pros and cons of smart beta strategies, generally agreeing on most points.

“The point of our whole exercise is check the price tag of what you’re buying,” said Arnott, chairman and chief executive of Research Affiliates. Asness cited value and momentum as two smart beta factors with the best outlook.

Ultimately, the panelists were aligned around on the notion that investors are prone to behavioral bias. Arnott said, “Evolution conditions us to want less of what has inflicted pain and more of what has given us happiness. You want to buy low and sell high, but we’re not conditioned to.” He advised against abandoning value when those shares are cheap. Asness agreed that behavioral biases are here to stay, but argued, “I think Rob is overconfident about our ability to take advantage of investors’ overconfidence.”