marcopolo wrote: ↑Sat Sep 19, 2020 3:42 pm
If someone did a study and came to the conclusion that "poor people are less intelligent" without controlling for lack of educational opportunities, access to nutritional foods, etc.
Then 5 years later looked into those items and discovered that when correcting for those things there was no link between being poor and performance on intellignece tests.
You think their initial conclusions are still correct, and consistent? And they can legitimately claim what they were saying was correct all along?
No no, this is completely different, I see your confusion. It's not that AQR found out something, then learned more, and revised their previous stance. AQR has since day 1 said the same message. It's just that
in the same paper, AQR said comments like "size doesn't work past beta and liquidity" and also said "but it does work with beta, liquidity and quality".
It's like the Doctor telling you "hey vegetarianism is associated with higher health. But it's actually because of more exercise". And then you'd respond "well, which is Doctor, does vegetarianism give more health or not? You sound very inconsistent".
Or using your example above, it'd be like a study saying "we find that poor people are less intelligent. But once we control for, say, country, we find that's not the case at all".
You're saying that's inconsistent. I'm saying it's not at all. But if you did take sentences out of context from that study, you might say "wait, they're saying poor people are less intelligent AND poor people aren't less intelligent".
marcopolo wrote: ↑Sat Sep 19, 2020 3:42 pm
If so, then you are right AQR is consistent.
I disagree, but we are each allowed our opinions.
Except AQR never even flip-flopped the way you describe above. Since the beginning, AQR has consistently said size works by itself, doesn't when you control for the confounding variables beta and liquidity, and does again once you add profitability on top. See for yourself:
1) Jan 2015: The Small-Firm Effect Is Real, and It's Spectacular
These assaults have rendered the pure small-cap premium as marginally significant, at best, and “not real” at worst.
...
The many formidable challenges to size all disappear with the introduction of the QMJ factor. It turns out that small stocks are quite “junky” versus their larger counterparts, and it is this exposure that is dampening their performance. Once you account for the QMJ exposure a large and significant size premium re-emerges.
TLDR: "FF size is very flimsy/weak once you control for beta and liquidity. But it's very robust if you add profitability"
2) May 2015: Size Matters If You Control Your Junk
The size premium has been accused of having a weak historical record, being meager relative to other factors, varying significantly over time, weakening after its discovery, being concentrated among microcap stocks, residing predominantly in January, relying on price-based measures, and being weak internationally. We find, however, that these challenges disappear when controlling for the quality, or its inverse, junk, of a firm. A significant size premium emerges...
TLDR: "FF size is very flimsy/weak once you control for beta and liquidity. But it's very robust if you add profitability"
3) May 2018: Fact, Fiction, and the Size Effect
FICTION: THE SIZE EFFECT IS LIKELY MORE THAN JUST A LIQUIDITY EFFECT
...
FICTION: THE SIZE EFFECT WORKS IN OTHER EQUITY MARKETS
...
Why does the size effect become significantly stronger when controlling for the profitability factor? Because, as Asness et al. (2018) showed, the size effect is confounded by a very powerful quality versus junk effect. They investigated the relationship between size and quality and found that controlling for quality not only resurrects the size premium and elevates it significantly but also helps resolve some of the aforementioned patterns associated with size.
TLDR: "FF size is very flimsy/weak once you control for beta and liquidity. But it's very robust if you add profitability"
3) September 2020: There Is No Size Effect: Daily Edition
We, consistently across both papers, find the simple small firm effect doesn’t exist, as small firms do not historically defeat large ones by more than their market beta. And we, consistently across both papers, find that small firms indeed look much more impressive than large ones if you also adjust for their lower quality (not generally what people have called the small firm effect!). The message is consistent and straightforward (if indeed more complicated than when quality is left out).
The problem is that people read the Fact and Fiction paper, read how they keep saying FF size doesn't actually work past beta but then claim it works (when added to quality) and they're like "wait OMG contradiction".
And there's no contradiction at all. None. Zero. Nada. Seriously, what do you want from these guys?

"... so high a present discounted value of wealth, it is only prudent for him to put more into common stocks compared to his present tangible wealth, borrowing if necessary" - Paul Samuelson