Away Goals Rule - Rationale

Rationale

The away goals rule is intended to encourage the away team to be more aggressive. In football, at least, it sometimes leads to a nervous first leg: the home team is unwilling to commit large numbers of players to attack lest they concede a goal, whilst the away team attempts to defend and snatch an away goal to aid them in the second leg. Such tactics arguably make the second leg more exciting, after a low-scoring first leg leaves both sides with a chance to win. There are sometimes debates over whether the away goals rule gives an unfair advantage to the team playing away first — with the other team squandering their home advantage in the first leg due to away goal fears — and this may be a factor in its somewhat patchy adoption for competitions.

There is also the issue that if extra time is played in the second leg, the away team gets an extra 30 minutes to take advantage of the away goals rule.

Anecdotal evidence certainly suggests that most teams feel an away goal puts them in the driving seat.