A Quick Check on Cheik

Cheik Tiote was widely regarded as one of the Premier League's success stories last season. However, the general perception amongst many Newcastle fans and the media is that Tiote's performance levels have dropped-off this season, with even Alan Pardew recently commenting that "this year he's struggled a bit". Given Newcastle's recent upturn in fortunes, brought about  by the arrival of several January transfers, Tiote might even find it difficult to regain his place in the team's starting eleven upon his return from the Africa Cup of Nations. Do Tiote's performance statistics agree with popular opinion, or can he regard himself as being treated a bit unfairly?

In this post I will therefore attempt to answer two questions:

1. is there evidence of a worsening in Cheik Tiote's performance levels, relative to last season?
2. are changes in Cheik Tiote's performance levels simply a reflection of a wider trend in performance levels for the entire team? (In other words, how have Tiote's performance levels changed since last season, relative to those of his team mates?)

In order to answer these questions, I'll use several measures that most football fans would probably perceive as being important indicators of performance for a defensive central midfield player. I'll show how these measures have changed between the 2011/12 and 2012/13 Premier League seasons for both Cheik Tiote and a number of his team mates (the "comparison group"). Rather than comparing raw numbers of activities (e.g. total number of tackles made) or average numbers of activities per match (e.g. average number of tackles made per match), I'll divide the total through by each player's total game time over a season to derive a "per minute" measure, so that changes in game time between seasons do not influence the results. The average measures I'll present are also game-time weighted. I'll restrict the comparison group to outfield  players who have played at least 500 minutes of Premier League football for Newcastle in each of the two seasons, so that the results are not skewed by extreme values. The results of the analysis are summarised in tables 1-6 below.

Table 1: Tackles per minute

Table 1 shows that Tiote has put in more tackles per minute this season than he did last season; his increase is the largest of the midfield players in the comparison group, and is bettered only by Danny Simpson and Papiss Cisse. However, table 2 shows that Tiote's increase in tackles per minute is accompanied by an increase in fouls per minute. His increase in foul rate is the fourth largest of the 13 players in the group, and is above the group average, but it is not as large as that of fellow central midfielder Yohan Cabaye.

Table 2: Fouls per minute

Table 3 illustrates that Tiote has increased the number of interceptions he's made per minute when compared to last season, and is one of only two players in the comparison group to do this. Meanwhile, table 4 shows that Tiote has been dispossessed less frequently than he was last season, and his decrease is the greatest of all 13 players in the group.

Table 3: Interceptions per minute

Table 4: Dispossessed per minute

According to table 5, Tiote has attempted more passes per minute than he did last season, and his increase is the greatest of all 13 players in the comparison group. On average, passes attempted per minute for the entire group has fallen since last season. However, table 6 shows that Tiote's pass success rate (the proportion of attempted passes that found a team mate) is down on last season, by 0.4 percentage points, whilst the average for the group is up, by 2.5 percentage points. Two other players in the group - central midfielder Yohan Cabaye and play-maker Hatem Ben Arfa - have also experienced falls in pass success rate, and in both cases the deterioration in performance is greater than that of Tiote.

Table 5: Passes attempted per minute

Table 6: Pass success rate

In summary, Cheik Tiote has made more tackles and interceptions per minute, and has been dispossessed less frequently, when compared to last season. However, he's made more fouls per minute than he did last season and, although he's attempted more passes per minute, his pass success rate has fallen. In areas where Tiote has improved, his improvement is typically greater than that of the majority of his team mates (he is in fact the biggest improver against some of the measures I've presented). Conversely, in areas where Tiote has deteriorated, his deterioration is also typically greater than that of the majority of his team mates.

Whilst an apparent decline in Tiote's performance - relative to that of his team mates - according to certain measures will probably align with the perceptions of many Newcastle fans, perhaps evidence that he has made relative improvements on last season according to other measures will be more of a surprise. It might also be worth noting that, for those measures against which Tiote has deteriorated, some of the players who have deteriorated more have largely been praised for their performances so far this season. This apparent differential in perceptions might be party explained by measures of performance not considered in this post, such as chance creation and shooting accuracy. Furthermore, it's likely that Tiote is a victim of the defensive role he plays in the centre of Newcastle's midfield, where every misplaced pass and every mistimed tackle is likely to be more costly to the team, and therefore be subject to a greater level of scrutiny, than those committed by his more attack-minded peers.