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In the beginning of the season, most Liverpool fans would grieve for Luis Suarez’s departure from Liverpool to Barcelona. He was the key factor leading the team to be competitive for the league championship in the last season. People might not be surprised with the decline of the team in the beginning of this season, especially with the come-back of Manchester United and arising of Arsenal. However, since Christmas, the team has recorded 9 wins and 2 draws, maintaining an unbeatable streak till now. This record is the best in the premier league at the same period of time, especially for their tremendous achievements on victories over Tottenham Spur, Southampton, and Manchester City. If we called Arsenal to be the devil for the 4th place, Liverpool is called the devil of Christmas. Now, let us take a look at this devil, and see what changes this team, and whether they will consistently perform in this high level.

According to our ANOVA table, the team did significantly improve their records. According to the tapply result, the team played as a mid-tier team, averagely losing 0.176 goal; and plays as a top-tier team in the recent games, averagely winning 1.36 goals. Here is a graph to display the result clearly,

Rplot

 

In this graph, we can see the average, 1st Quartile, and 3rd Quartile of recent game results are significantly greater than the ones of the previous game. This graph proves that the team performs much better than before.

According to the ANOVA result, the team tends to play in mid, reducing the offense from the two wings (the number of crossings decreases 9.422, and the number of blocks from the opponent team decreases 2.877). They do not always challenge the aerial duel and sent players, who are less powerful for aerial duel, onto the field (the winning percentage of aerial duel decreases 7.412%). In general, Liverpool plays the ball rather carefully, not to challenge the long pass that frequently as what they did previously. This play style indeed helps the team improve their performance. According to our statistic evaluation model, the team is more comfortable when they play the ball on the ground rather than aerial duel. When they have high aerial duel ratio advantage, the team tends to score less and be scored more than usual. Therefore, this change can significantly improve the team performance.

Let us see if the team will consistently play in a high level performance. We will use simple K-means clustering to work on this case. We will have 4 clusters in this case.

Here is the clustering assignment of each game,

QQ截图20150310205115

Here is partial result of the clustering centroids,

QQ截图20150310205305

We can see that the team play rather strong on performance since the 16th game, all of the games either locate in cluster 1 or cluster 2. One thing we need to notice is, before 16th game against Arsenal, most of the home games also locate in cluster 1 as well. The major difference took place is in their away games.

Let us take a look at the major performance indicators between cluster  0 and cluster  2&3.

We work on the ANOVA again to see the difference between cluster 0 and cluster 2, and the difference between cluster 0 and cluster 3. According to our result, the team does not perform significantly different in cluster 0 comparing to the games in cluster 2, except the aerial duel winning ratio. However, the opponent teams play in cluster 0 significantly worse than what they play in cluster 2, including Passing Accuracy(decreases 3.6%), Chances Created(increases 1.625), number of Takes On(decreases 3.312), Aerial Duel winning ratio(6.854%), number of Fouls (increases 2.083).  Similar situation happens in the difference between cluster 0 and cluster 3 as well, the opponent teams perform significantly worse than they did previously in their home field.

One thing needed to be noticed, is that the passing accuracy does not significantly improve in the recent games even though the team chosen the players who is less strong in Aerial duel. In our general thought, players who are less strong should somehow have great techniques. It does not come out so true in this case.

The second thing we should notice, is that the team performance does not highly rely on whether they play at home or away. Their defense would be scored less (0.887 goals) when they played on their home field. As the clustering results above, we can see that Cluster 0 even has a better result than Cluster 1 does. Considering the recent game result, we can believe that the team has overcome the troubles while they play away.

Therefore, we should somehow know that the team would not fall too much in the coming future, since they have been playing so consistently in their home games, and proved that they perform regularly away as well. This team will be a major competitor for the top 4 spots in the league based on this performance now. However, we cannot believe the team can continue this unbeatable streak since the opposing teams can get familiar with the tactical change when they play in their home field.

As a fan of Liverpool, I definitely want to see Steven Gerrard will leave the team with the happiest smile in the end of this season.

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