How many goals can you expect in the 2nd half?

Feb 27th, 2012 - Posted by Andrew_Brocker in Football

bettingexpert blog editor. Always taking the alternative route to finding the value.

What's the chance of a Premier League match going over 2.5 goals if no goals are scored in the 1st half? What if 1 goal or 2 goals are scored in the opening half? Today on the blog, Andrew attempts to answer these questions and more.

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I've written a few articles in the past about the occurence of different halftime results in the Premier League, mainly looking at the potential for a drawn result at the half.

Today I thought I would shift my attention to the 2nd half and in particular the occurence of matches finishing over 2.5 combined goals given a particular halftime scoreline. I will be breaking down matches by the number of goals scored in the opening half (0, 1 or 2) and cross referencing those halftime results with the pre-match fulltime Over 2.5 goals odds.

In the course of this analysis, I will be using results and odds from the last 10 Premier League seasons, dating back to 2002/2003.

Not every half is the same

So let's begin with a simple breakdown. The chart below shows that occurence of a Premier League match finishing over 2.5 combined goals depending on the number of goals scored at halftime.

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As you would expect, the occurence of matches finishing over 2.5 goals is strikingly different depending on the number of goals scored at the half. When a match is scoreless at halftime, over the last 10 seasons a Premier League match would end over 2.5 goals just over 17% of the time.

With 1 goal on the board, the occurence rate climbs to just under 43% while with 2 goals on the board, in the last 10 seasons of Premier League matches, the game would end over 2.5 goals just over 79% of the time.

However, not every match is the same in terms of Over/Under expectations. Some matches the odds makers assess a higher expectation of goals, while in other matches the expectation of goals is less. We will now use pre-match fulltime Over 2.5 goals odds to assess 2nd half goal expectations depending upon the halftime goal total.

Expectations with 0 goals at the half

So let's begin with scoreless 1st halves. The chart below shows the occurence of matches finishing over 2.5 goals when the match was scoreless at the half. We have then broken results down into the range of pre-match Over 2.5 goals odds displayed as the implied probability of those odds. What does that mean? Well the implied odds are calculated as 1 divided by the decimal odds (i.e 1 divided odds of 2.15 gives us an implied probability of 46.51%). I have then grouped each odds range in increments of 2%, with the range starting at 64% and above (odds of around 1.55), extending down to 44% or less (odds of around 2.25) .

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Here we can see a clear trend that the occurence of matches ending over 2.5 goals is clearly greater when the implied odds are above 54%, with scoreless 1st halves ending with a match of 3 or more goals at a rate of around 23% to 26%.

On the other hand, matches with an Over 2.5 goals implied probability of 54% or less, end with 3 or more goals around 15% to 16% of the time when without a goal scored at halftime.

Expectations with 1 goal scored at the half

So now let's turn to situations where there has been 1 goal scored at halftime. The chart below shows the occurence of matches with 1 halftime goal finishing over 2.5 goals depending on the pre-match Over 2.5 goals odds.

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Unlike matches without a goal scored at halftime, the trend when 1 goal has been scored isn't as stark. We can however see that a trend exists similar to scoreless halves. Breaking the numbers down and dividing matches between a pre-match implied odds of 52% or less and implied odds of 53% or higher, the occurence of matches ending over 2.5 goals is quite different.

In matches where the pre-match Over 2.5 goals implied probability was 52% or less, the occurence rate of matches finishing over 2.5 goals was just under 41%. In matches where the pre-match implied probability was 53% or higher, these matches ended over 2.5 goals almost 48% of the time.

Expectations with 2 goals scored at the half

Let's finally look at matches with 2 goals scored at halftime. Again we will break the results down depending upon the implied probability of the pre-match Over 2.5 goal odds.

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As you would expect, the occurence of matches finishing over 2.5 goals is much greater with 2 goals on the scoreboard at halftime. And again, although the trend is no so stark, we can see that the occurence of matches ending over 2.5 goals is a little less when the pre-match expectation of goals is less, even with 2 goals already on the board.

If we breakdown the results as we did with 1 goal scored, we see that when the implied probability of a match ending over 2.5 goals is 52% or less, the occurence of the match ending over 2.5 goals is just under 78% while when the implied probability is 53% or more, the match ended over 2.5 goals just over 82% of the time.

Concluding thoughts

Although the analysis provided demands deeper research, it is hoped that the data presented can assist punters in assessing and finding value in the in-play Over 2.5 goal betting markets. It's also a good reminder of how historical odds can be used to analyse past trends and assess future potential, especially in markets such as in-play goal totals, where the vast majority of the public are largely unaware of the historical occurences.

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