I crunched the numbers on WC intercontinental playoff victories by 1st-leg home teams vs 2nd-leg home teams to see if there was an advantage. Full details here.

TLDR;
Conventional wisdom says it's better to be home for the 2nd-leg.

There is a lot of research into this in the case of UEFA Champions League 2 leg ties. Overall it finds there is no advantage either way.

In WC intercontinental playoffs the 2nd-leg home team has won 56% of the time. If the favorites win this week (Australia and Peru) that will be 61%.

Personally, always believed that playing home in the second leg in much much better. 

Yeah pretty much.
You have to grind out a result in the away league, maybe score a goal if your lucky and come home with a tidal wave of support.

Always better home 2nd leg plus that data sucks because half of those games there is a major disparity in the quality of the teams.

 If they are even like it appears with us this time the 2nd leg host would have the advantage. 

The thing that I never realised before is that goals in extra time count as double in the event of a draw. To me this is a significant advantage

It means either the home team has to win outright in extra time or hope for a scoreless 30 minutes and penalties

I hear people saying away goals counting as double in extra time is not fair because the 2nd-leg away team gets more minutes in which their goals are doubled, but I disagree.

The extra time also means the 2nd-leg home team gets more minutes of play at home. It means over the 2 leg tie the 2nd-leg home team gets 57% of the total game time at home.

When two teams are deadlocked after 180 minutes home and away it demonstrates that the home ground did not have an advantage

So it is a case of giving one team a real advantage (score tied extra time = progression), and the other team something that has proven to be superficial

It's more likely that home ground advantage was equal for both teams and cancelled each other out because each team had the home ground advantage for the same amount of time. With extra time in the 2nd leg one team will have home ground advantage for longer than the other (which I think is fine because the other team gets away goal advantage for longer than the other).

Throughout the whole 180 minute tie the home team had home ground advantage and the away team had away goal rule advantage. It makes no sense to remove 1 but not the other in extra time.

There was a study on it published this year. 

"Robust analysis of second-leg home advantage in UEFA football throughbetter nonparametric confidence intervals for binary regression functions"
https://arxiv.org/pdf/1701.07555.pdf

"The analysed data, all drawn from Kassies (2016), include all match results fromUEFA Champions and Europa leagues from 2009/2010 through to 2014/15 and the UEFA coefficients ofall clubs which took part to some European competition for those seasons"

But yes it found Second Leg home has advantages but it is not a "Major advantage" on average teams playing at home score more goals in the second leg than teams playing at home in the first leg. Also teams playing away in the second leg score less goals than teams playing away in the first leg. 

To tell you the truth I think in this case  the disadvantage is playing the 2nd leg at home. The long travel obviously affects both teams and 
the games are pretty close together. The difference is that we have to travel there and back home while Honduras only need to fly here in 
order to complete the tie. The difference between this game and the Uruguay leg in 2006 is that there are enough commercial flights that the
Hondurans will still make it here in relatively the same shape as the Aussie boys. 

Not really statistically significant.

Within the bounds of normal error.

If it was up towards 13-14 I'd be excited.

hmm, they will arrive in Sydney 24 hours later than us and they will have been in economy (the federation is broke AF).

Wouldn't have mattered anyway as the vast majority of our team dont play in Australia so they would've had to travel here from europe/asia anyway. Its only a benefit for them because their players aren't good enough to get out of honduras.

The away goals rule is partly there for the sake of trying to balance out the advantage that a team would have playing the second leg at home. By the time you get to the second leg, the home team has all the support, but the away team is the only team left that can score away goals. You get those situations where an away team scores, and not only do they go ahead on aggregate they also go ahead on away goals, making that goal almost count as two goals. It's fair enough that they continue into extra time, because the home team gets extra time / penalties on their home ground.

For us travelling to Honduras, it encourages us to go on the attack as well. A 2-2 draw in Honduras gives us a big advantage, because they'd have to score 3 to go ahead on away goals. Losing 3-2 away would almost be better than a 0-0 draw...

Hard to say. Have a glance at Cahill's social media account.

He has uploaded a photo on the flight. In addition to the leg room and elevated legs, he has this machine to stimulate blood flow in his legs. I can't recall what it's called. But there's a suction cap thing attached to his legs. There are small volts of electricity making the blood flow. My physio had me using the same thing when I ruptured my ATFL in my ankle. I was able to play again within weeks (and we're talking about an awful tear). It makes a hell of a lot of difference.

I doubt you can bring a bunch of those devices onto a commercial aircraft. Let alone massage therapists, physios, oxygen masks (not for emergency use). It all adds up.

Having said that, if the Hondurans are tough and good footballers, there's no reason they can't inflict some damage to Australia in Sydney (even without those advantages).

They also get to host a potential penalty shoot out. So I think its fair.

15 years later, I'm still upset that Farina chose to play the first leg of the Uruguay game at home.   :angry:

The last time Honduras had to travel outside of the Americas was exactly 3 years ago when they lost 6-0 to Japan in Tokyo in a friendly. We're used to long travel. They certainly are not. Lets hope it helps us.

Must freak a lot of them out being so far away from home for the first time.

So with a couple more intercontinental playoffs behind us it's now 61% in favor of teams who play the 2nd-leg at home including 6 out of the last 7.

Full details https://bitedge.com/blog/second-leg-home-advantage-in-world-cup-intercontinental-playoffs/

Is it the same in club competitions? 

Form the article

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.