A question that should be easier to answer than it is: Are Chelsea succeeding?
For most teams, it's close to black and white. Wolves, whom Chelsea just beat 3-0? Massive failure: no wins yet, already fired their coach, probably getting relegated. Sunderland, who just tied Arsenal and came into the season with relegation as their most likely probability? Massive success: They're in fourth place and barring a total meltdown, they've all but clinched another year in the top flight.
To render a reasonable judgment for 19 of the 20 teams in the Premier League, all you need to ask is: Are they better than last year?