Size is Relative

If you asked a real historian to name the biggest person in history you're unlikely to get past what do you mean by "biggest"?
As in height?
Do you really mean who was the most influential?
That would depend on your perspective as many considerations of size do.
And what perspective would that be? European, African, Middle Eastern or East Asian?

And all of this is before we even get to the issue of whether this is a valid question to ask. You probably don't think that it is, but if you really did want to ask "who's the biggest person in history?", you now don't need to bother as Steven Skiena and Charles B Ward have produced a pre-Christmas offering that will answer just that question for you. It's called "Who's Bigger? Where Historical Figures Really Rank" and - probably not just because it's Santa season - puts Jesus Christ on top.

Putting aside any debate about whether there's a god, and/or whether he's the offspring of that god, as there's no independent evidence to support that he even existed, why do the authors consider Jesus to be a "historical figure"? Napoleon and Muhammad fill second and third place, with William Shakespeare and Abraham Lincoln making up the top five, and quick reading shows the next ninety plus to be actual people, so how did they come up with this list, if the "winner" isn't (wasn't?) verifiably a person at all?

Fortunately, they've answered that one for us, by explaining how utilising a statistical approach, inspired by Google's method of ranking web pages gives:

"We ranked historical figures just as Google ranks web pages, by integrating a diverse set of measurements about their reputation into a single consensus value.

Significance is related to fame but measures something different. Forgotten U.S. President Chester A. Arthur (who we rank as the 499th most significant person in history) is more historically significant than young pop singer Justin Bieber (currently ranked 8633), even though he may have a less devoted following and lower contemporary name recognition.

Historically significant figures leave statistical evidence of their presence behind, if one knows where to look for it, and we used several data sources to fuel our ranking algorithms, including Wikipedia, scanned books and Google n-grams.

To fairly compare contemporary figures like Britney Spears against the ancient Greek philosopher Aristotle, we adjusted for the fact that today’s stars will fade from living memory over the next several generations. Intuitively it is clear that Britney Spears’ mindshare will decline substantially over the next 100 years, as people who grew up hearing her are replaced by new generations. But Aristotle’s reputation will be much more stable because this transition occurred long ago. The reputation he has now is presumably destined to endure. By analyzing traces left in millions of scanned books, we can measure just how fast this decay occurs, and correct for it."

So it's not just the inclusion of people who may or may not have actually existed that's the book's only problem: there's also the issue of conducting a study of the biggest figures in history from a completely English-speaking perspective. No wonder the full list is mainly white, male and American.

If nothing else, the study has the potential to be the basis of a critical thinking workshop next year - possibly what's wrong with this list and why? - but doesn't do anything to answer the question the authors set themselves.
What's for next year?
Who's the biggest Belgian in history?
Poirot?