Since most sports events is postponed, now we have time for this interesting discussion.
When we talk about home court advantage, first thing which comes to my mind is support of local fans. But there is much more things which are ore or less important. In away games players are travelling by planes and buses, they spend time on airports and traffic jams. Offcourse it doesn't help to get rest and prepare for the game. On international games, time zone difference is also a factor.
While home team have advantages - players sleep in their own bed instead of hotel, eat common food, arrive to stadium like every day. They have common suroundings, same dressing room. In basketball even basket rims are different in every arena - it's big factor.
In football, quality of pitch is another factor. Maybe it's less common in top leagues when we almost all teams have top notch pitches, it's more about lower divisions and less popular leagues, when sometimes away team arrive to play in potato field. In some leagues, like in my country, several teams play on artificial turfs - it's huge advantage against teams which play and prepare for the game on natural grass. And vice versa.
On the other, home court isn't always is advantage, because players get additional pressure and players sometimes fail to handle it. First example which homes to my mind is Brazil football team in World Cup 2014. But it's not that frequent cases - there is not so many teams which play better away than at home.
I know Barca has a huge pitch. It was intentionally designed as big as possbile to suit the playing style of them. In german Bundesliga you have Freiburg and the pitch in their stadium has some gradient (it's around 1m iirc), so for one half you would always have to play a uphill a bit.
I knew that pitches have different sizes, but didn't knew that such big difference is allowed. But I may be wrong, but at least in biggest leagues sizes of pitches are pretty much similar size and few meters difference isn't very big factor. Now I can't find all these dimensions compiled into single place and I'm lazy to check wiki page of every stadium.
It's interesting thing about Freiburg pitch, for me it's strange that's allowed on such big level competition.
As you can see the factor is 1, meaning home advantage doesn't have any influence on any game. Why is that? The Maltese Premier League is a very small league, all games are played in the same stadium, so there is no "home team" at all.
Actually, it's not true, in Maltese Premier League there is 3 stadiums is used
https://en.m.wikipedia.org/wiki/Maltese_Premier_LeagueBut probably this fact doesn't makes big difference.
One sport where home field advantage is not such a big factor is ice hockey. But even here there is a different between European ice hockey and the NHL. In the NHL it happens quite often that the better team losses at home against a team who is the underdog. But NHL teams travel a lot and play 3-4 matches a week. This fatigue can also be the reason why such things happen. I like the changes that NHL made for this season. The teams now play a few successive matches at home and than they go for a little away tour. Once this away tour ends and they play in from of their home fans again, surprises happen (yes I am looking at you Colorado).
I think home field advantage is not that big factor in NHL (in NBA too) because of long regular season. Cost of loss isn't that big there, so this is why we see these upsets so often. Things usually change when playoffs begin.