The 2018 Writers Guild of America Awards take place on Feb. 11 with simultaneous ceremonies held in both New York and Los Angeles. Only scripts written under the guild’s guidelines or those of several international partners are allowed to vie for these awards. As such, these kudos are not the most reliable barometer of the Oscars.

In the past nine years only 59 of the WGA nominees have numbered among the 90 screenplays that reaped Academy Awards bids. Indeed, 2014’s Oscar winner for Best Original Screenplay, “Birdman,” was deemed ineligible. Likewise for one of this year’s leading contenders for that award: “Three Billboards Outside Ebbing, Missouri.”

On the television side, the leading nominees are “Better Call Saul,” which competes for best drama series writing as well as for two individual episodes and “The Americans,” which is up for both overall drama series writing and an individual episode. Over in comedy, reigning Emmy...