After numerous subjective discussions (heated arguments) with friends of mine comparing EPL to La Liga that could only serve to break friendships and bruise throats, I decided to actually do some work and analyze the quality of the two leagues.
Disclaimer: I really like La Liga, and I really like Barcelona.

There are two main equally important components of the quality of a soccer league:
1. Strength of the top teams: There may be soccer leagues in India and Egypt with fierce internal rivalries and healthy balance in strength, but if the top teams itself are weak, the whole league is weak. To paraphrase Radiohead, the best they can ain’t good enough.
2. Competitiveness: This is the reason there is no Bundesliga in this discussion. A league is fun only if the day to day is exciting.

Intuitively, point 1 goes to La Liga, while point 2 goes to the EPL. But let’s allow stats to join the discussion.

I collected the final season tables for the two leagues from 1997-98 to 2013-14 in order to study the aggregate over these 17 seasons. Now some people may say that this is not recent history, but if you really want to talk stats, you need to have more data points. Otherwise the point of this article is moot and we can all go back to arguing relentlessly.

Also, I defined something called Nu Points, because I don’t like the current point allotment for WDL (3:1:0). I either want to make it more balanced (4:2:0) with every match getting 4 points (Nu Points), or more win heavy (4:1:0) with every win adding more weight in case of an imbalance (Wh Points).

So here is the aggregate table, and it is a counter intuitive curveball:

Standard deviation is a metric of competitiveness, the lower it is the tighter the league and fiercer the competition. And by the cock of Zeus, it is a result we did not expect to see! La Liga has a lower standard deviation compared to EPL. But we all know that EPL would be more competitive, so what the hell is going on?

The answer lies in the details, and how aggregated statistics can sometimes obfuscate the story than reveal it.

Here is the breakdown of the team wise statistics for the Nu Points and Wh Points for the top 20 teams in each league (top teams defined by the number of seasons played, followed by average points).

And now we see what is going on. FC Barcelona and Real Madrid are dominating the Liga at the expense of the other teams (this is even more stark when you consider the Wh points), but the competition among the rest is very fierce and most of them are even. This contrasts with the EPL, where the top 4 are much stronger (in the vein of RMA and FCB) and there is an unmistakable steady decline in the quality of the other teams. This leads to the higher standard deviation in EPL compared to Liga.

So clearly, with similar coefficients of variance, statistically speaking, both leagues are imbalanced. And no sane person should disagree here. This is a general problem with football leagues as the distribution of funds happens to be in a positive feedback loop which can only be broken by the infusion of big money (Chelsea / Man City) into some of the lower teams. What gives EPL the perception of being more competitive is the closeness of the top four compared to Liga. All of the top four in EPL (now five with Man City joining in with a gorgeous Upper Limit) are quite close and are offered decent shots at the pole position. This is completely unlike Liga where RMA and FCB are thoroughly dominating the minions. Since competition for the top is what matters, EPL is clearly more competitive.

From 1997 to 2013, I would say that the best of EPL has been as good as the best of Liga on average (key here being on average, maybe Liga narrowly edges EPL). If that is an assumption we can agree upon, then clearly EPL offers more in terms of competitiveness than Liga.

Point 1: Tied (Liga edge)
Point 2: EPL wins where it matters

Overall winner, EPL.

Congrats EPL! But trust me, if you want to learn how to play good and enjoyable football, watch the current majesty of Barcelona. I just had to fucking say that.