Here are the factors, and the stocks, that will help you play the COVID-19 market

If we’re currently in the early innings of a bull market, as some analysts think, how should you invest?

There are big themes to consider: “work from home,” for example. And there are stand-out single stocks, like Amazon.com Inc. AMZN, -0.98%. But an approach that’s somewhere in the middle is factor investing — picking companies according to their performance qualities. Analysts at Ned Davis Research on Wednesday published a research paper on the factors to consider investing in now, and the stocks that fit those criteria.

Investors should select companies...