hockey), playoff series are often held with a nearly equal number of games at each team's site. However, as it is usually beneficial to have an odd number of matches in a series (to prevent ties), the final home game is often awarded to the team that had the most success over the regular season. An example is UEFA Champions League and UEFA Europa League home and away legs, with weaker teams often beating the favourites when playing at home. The World Cup victories of Uruguay (1930), Italy (1934), England (1966), Germany (1974), Argentina (1978) and France (1998) are all in part attributed to the fact that the World Cup was held in the winner's country. A 2006 study by The Times found that in the English Premiership, a home team can be expected to score 37.29% more goals than the away team, though this changes depending on the quality of the teams involved. Others have suggested that the increase in British medals during the 2012 Olympics may have been impacted by home court advantage. (However, having home court did not help Canada at the 1976 Montreal Olympics, the only Summer Games at which the hosting country failed to win a single gold medal.) The strength of the home advantage varies for different sports, regions, seasons, and divisions. For all sports, it seems to be strongest in the early period after the creation of a new league. The effect seems to have become somewhat weaker in some sports in recent decades. Adams & Kupper (1994) described home-field advantage as an expertise deficiency. They demonstrated that, in theory and in practice, home-field advantage decreases as superiority of performance increases. They also showed that home-field advantage is not applicable for no-hit major league baseball games for pitchers who either replicated performance by winning two or more no-hitters or amassed a large number of career wins. Their general finding was that home-field advantage is a metric for the inability to maintain performance independent of environment and that this metric is inversely related to variables of expertise. In recognition of the difficulty in winning away matches, cup competitions in association football often invoke the away goals rule. Away goals can also sometimes be used to separate teams level on points and goal difference in league competitions. Causes Factors related to the location and the venue There are many causes that attribute to home advantage,