Is Hull City the Worst Team to Make the Championship Playoff Final in Many Years?

And what would it mean if Hull really is that bad?

Hull City will probably face Middlesbrough in the Championship playoff final this coming Saturday, with promotion to the Premier League on the line. There has rightly been considerable coverage of the non-football side of this match. Boro in fact lost to Southampton in the playoff semifinals, but members of the Middlesbrough staff caught a Saints assistant coach spying on their training session before the match. The Football League held an inquiry into this allegation and on Tuesday officially removed Southampton from the playoff final and reinstated Boro. This matchup is still not entirely certain, as Southampton has appealed the decision and the Football League will need to rule on that appeal. I give the whole SpyGate saga my highest recommendation, and in particular don’t miss the picture of the Southampton assistant coach taping the Boro training session on his iPhone.

But this is an analytics blog, and there is in fact a soccer analytics story here too. Hull City has bad underlying numbers.

The Tigers managed to finish 21-10-15 in the Championship and snagged the final place in the playoff with a sixth-place finish. But even the most cursory look at the table suggests Hull City is not like the others. The teams just ahead in the table—Millwall, Southampton and Boro—had plus-15, plus-26 and plus-25 goal difference respectively, while Hull outscored its opponents by only four more goals. The teams that finished behind Hull—Wrexham, Derby County and Norwich City--look to be much more at Hull’s level, with plus-4, plus-8 and plus-7 GD.

The simple tallies of goals for and against place Hull City as not just the weakest side in the playoffs this season, but one of the worst teams to make the Championship playoffs this century.

And the underlying numbers are worse. The Tigers have conceded 685 shots while attempting just 517, for a minus-168 shot difference. Only relegated Sheffield Wednesday and 19th-place Charlton Athletic had worse shot numbers. Expected goals calculations only slightly improve the case: Hull City has the sixth-worst non-penalty expected goals difference in the league, at about minus-13.¹ These are not the usual numbers of a playoff team, and certainly not of a promoted team.

Should the Tigers win the playoff final, they would be the worst promoted team by expected goals difference in the last 13 seasons, by a wide margin. No team has been won a place in the Premier League since 2014 with a negative expected goals difference, and Hull City at minus-13 would be a little more than 18 goals worse than the previous record-holder.

Only one team since 2001 has been promoted with fewer goals scored than goals conceded: Huddersfield Town in 2017. Huddersfield did have at least a positive non-penalty xGD that season, although Huddersfield’s xGD is still the second-worst of newly-promoted teams over this period. Where the Terriers lucked out was in the playoff final draw, as Reading won the other semi-final. That Reading side is probably the most comparable team to Hull City in the recent history of the Championship playoff. The 2016–17 Royals managed to finish in third place despite a plus-4 goal difference, and their minus-21 xGD and minus-146 shot difference indicate they were probably fortunate to outscore their opponents at all. Huddersfield, despite roughly even goals and expected goals difference, was rightly favored in that playoff.

What Do Bad Numbers Mean?

It is notable that among the promoted teams with the worst Championship expected goals difference statistics, several managed to secure safety in the Premier League for another season. Huddersfield survived for a season before going back down. Burnley under Sean Dyche had multiple seasons in the Premier League, and Nottingham Forest even qualified for the Europa League this season. Sunderland, having put up only a plus-11 xGD last season, currently sits in 10th place. While none of these teams had underlying numbers quite as poor as Hull City’s, the list does offer some hope.

In particular, it raises a broader question. Do the best promoted teams have a better chance at survival in the following season, or are their other factors which actually drive Premier League results? What should we expect from a team like Hull City if they do win the final?