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One-goal and two-goals lead analysis

Continuing on my football resultss analysis, I want to analyze 1-goal and 2-goals lead. The main question is : does every score yields the same winning chance? Of course we keep scores with the same differential, for example home team is one goal up.

So I ploted on the same graph the Win% for 1-0, 2-1 and 3-2. First thing you will see in the graph below is that 2-1 data starts at the 15th minute and the 3-2 data starts at the 45th minute. All data points are regrouped in 5-minutes window to correct for the sample size.




What you see is that basically, Win% increases over time. But something more interesting is the trend. It seems that when the score is 2-1, the home team has less of winning (or to draw, as I count a draw as half a win). The difference is slighlty over 5%. When the score is 3-2, the curve is also below the 1-0 curve for most points.



When building nice fitting curve for 1-0 and 2-1, the trebd is clearer. Even if the effect is not huge, it is interesting to note. I didn't add the 3-2 curve, because there isn't a curve that fits nicely enough to allow comparison.
So in fact 1-0 is not the most dangerous lead, in fact is gives the home team a bit more chance to win.


Now we can do the same thing for a two-goals lead.



Here the graph is more interesting than the first one. First we see that when the home team leads 4-2, the chances of winning are reducing by an average of 30% until the 60th minute. After, the winning chance is reduced by a tinier amount.  We can use the trendlines to build nice curves to help us compare the different scores.

 

What we see is that, the chances of winning decrease when there are many goals scored. Maybe it is due to excellent strikers or poor defenders. As previously the less dangerous lead is 2-0. This means that you want less goals scored in a game to maintain the highest chance of winning a game.

So to conclude, we saw that all the different leads yield different winning chances. In fact the highest chances come from the lower scoring games, here 1-0 and 2-0. So managers should take defensive options to ensure the three points rather than trying to score more. Even if winning chances increase when the lead increases from say one goal to two goals, here the point is to compare the same lead.
So to increase winning chance, one wants to score. To keep the highest winning chance, one wants to avoid high scoring game.


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