Saturday 16 January 2016

Stoke, Four Seasons in One Day.

So far this season Stoke have been variously described as relegation candidates (six points from the first seven matches), mid table fodder (19 from 14 games), potential Champions League qualifiers (32 from 21) and as a side that raises their level of performance against top teams, but loses against lesser lights.

Each description has to a degree been legitimized by data driven evidence, usually based around the team's current record or in the case of the latter, cherry picked evidence based on a relatively small sample of matches.

Gaining less than a point a game, as they did in the first seven matches is relegation form in a normal season, but then Stoke won nearly two points per game in their next seven contests.

Champions League form combined with relegation form to leave them safely in mid table.

Similarly, the new found, but almost certainly transient reputation as scourge of the best owes much to two high profile televised victories against the two Manchester clubs. The red side of which has also lost to Bournemouth and Swansea.

Encompassing the traditional big five of Chelsea, Liverpool, Arsenal and the two Manchester clubs and including cup ties, Stoke has a success rate during 2015/16 of 50%. If the actual top five is used the success rate remains the same.

Stoke, Probably Still Mid Table and Looking Upwards.
Should Stoke defeat Arsenal on Sunday, the latter success rate could rise to nearly 60%, but defeat may see it fall to just above 40%, providing useful numerical evidence for whichever narrative you wish to push. But perhaps more indicative of the tendency for rates derived from small data sample to bounce around with the addition of a single result.

Following Stoke's win over Norwich, their success rate against the current bottom seven sides rose to 75% or just 60% if you care to include 8th from bottom WBA, against whom the Potters have played with 17 rather than 20 outfielders for a large part of their two encounters.

In short, "solid" trends and soundbite labels can quickly become nothing more than noise going forward.

Small samples should not move the needle much. A side may record results typical of a bottom three team or a top four contender for a small run of games, without either being indicative of a sea change.

How Stoke's Win% May Have Changed with Prior Knowledge of their 2015/16 Performances.

In the table above, I've included the probability that Stoke won each of their games this season as judged by the bookmaking markets.

I've then recalculated the win odds for Stoke based on the accumulated shot data of the Potters and each team they have played over the entire 2015/16 season to date to see if there is a substantial difference between the two sets of estimates.

In twelve cases Stoke has a higher chance of winning based on the January ratings of all 20 teams compare to the odds quoted on the day. Nine matches give their opponents an additional edge compared to actual match day odds.

So as Stoke's perceived quality has shifted over the season, so has that of the remainder of the Premier League. Some teams, notably Chelsea, Villa and Newcastle have become poorer relative to the market estimation of their abilities when they played Stoke and some, Watford, Leicester and WBA have shown relative improvement.

This shuffling of the performance pack has left Stoke worse off than generally expected with Leicester compared to the prevailing wisdom when they met in mi September, but possibly better off with Chelsea.

Overall they have a net tally that leaves them in a similar mid table standing to previous recent seasons, regardless of niche televised heroics and failure to beat the new, long ball version of WBA.

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