6.4.1 Estimation of fixed effects Heterogeneous team ability is a possible explanation for the result in Section 6.3. That result simply indicates that the more goals a team scores, the higher the probability that it will score more. However, teams that can score more goals also indicate teams with greater ability, or just greater scoring ability, than their opponents. As mentioned in Section 6.1.1, it is very natural that the higher ability team will score more, even though that stronger team has decided to defend more. Therefore, we need to control for this in the estimation.
This problem is similar, but not identical, to the problem identified by Heckman and Singer (1984), that heterogeneous subjects will tend to yield decreasing hazards because a longer time of no failure indicates that the particular sample is intrinsically not likely to fail. Here, heterogeneous teams tend to yield a higher hazard of scoring for the leading team because such teams are intrinsically more likely to score. *For the estimation controlled for fixed effects, a series of dummy variables are added. Two dummy variables are added for each team, one for home ground and another for away ground (with the exception of Manchester City to prevent colinearity and act as baseline hazard). * As there are in total 25 teams6 involving in the English Premiership, there are 48 dummy variables added. Similarly, there are 22 and 25 teams in the German Bundesliga and Spanish Primera Liga and therefore I add 42 and 48 dummy variables respectively. Fitting the model by these dummy variables only can yield the ability difference between teams. Manchester Cityâs hazard ratio is equal to 1 in all columns because it is the benchmark. Arsenal is obviously a strong team as it has very high hazard ratios for scoring (1.40 of Manchester Cityâs hazard at home) and very low hazard ratios for being scored against (0.81 of Manchester Cityâs hazard at home).... I am currently modelling soccer scoring process, may I know how do I set a variable as baseline hazard benchmark (as Bold characters inside above articles)? Hope some body willing to share your precious ideas. Thanks. -- View this message in context: http://r.789695.n4.nabble.com/Survival-Analysis-for-soccer-scoring-process-tp3801400p3801400.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]]
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