European club home and away ties

I wanted facts and found a lot of resources, including peer reviewed academic research, about the same question in regards to the UEFA Champions League 2-leg ties (and the previous versions of the same competition).

Overall studies and results show there is no advantage to playing the 2nd-leg at home. One older study disagrees and suggests that since the 1950s the 2nd-leg home team wins an adjusted 53% of ties. However, they find this advantage has become nonexistent in the last 20 years, which is what other studies suggest [1][2].

That’s all well and good for European club football which often includes ties between teams from the same country. However, home advantage is more pronounced in intercontinental playoffs because the climatic differences, cultural differences and travel times are so much greater.