I am not busting myths by saying that Argentina is not the same team with and without Lionel Messi. The Albiceleste are currently experiencing a rather difficult qualifying campaign for the 2018 World Cup and lot of the blame goes to the absence of La Pulga. Argentina won three out of three games when the man from Barcelona was playing (Bolivia, Chile and Uruguay) and only one of the seven in which he was not present (Colombia, 4 draws and 2 defeats). Argentina have only scored 11 goals and besides Messi (2), defender Gabriel Mercado (2) is the only player to have scored more than one goal.
Let’s take a loot at the numbers of Argentina with and without Messi, over a longer period. Since Lio’s debut on 17 August 2005 his country has played 158 games. Messi appeared in 114 of those, but for the comparison I will only consider the games in which he played at least 30 minutes. Per tournament this is the percentage of games Messi played at least 30 minutes:
If it was not clear before; Messi mainly plays official games (81%) and makes less appearances (53%) in friendlies. In total he played at least 30 minutes in 68% of the games. The following table shows the performance of Argentina when he is and when he is not.
You can see that Argentina slightly wins more points per game when Messi is present that when he is not, but the difference is not beyond imagination (0,10 point, or a 5% increase). If we look at this stat per tournament we see where the difference is made:
And here’s a graph comparing Argentina’s points with Messi’s points, both averaged over the last 15 games in each points of time:
There seem to be timers where Argentina performs better without Messi (e.g. 2009, 2010 and 2015) and times when it is the other way around (2011, 2012 and 2016 (all WC qualification years)). As seen earlier the Messidependence-effect comes to light in the South America World Cup qualification. Probably no coincidence as at least eight out of ten matches are against highly rated opponents (probably a higher percentage than even World Cup).