So goes January” is as old as the hills! This popular myth says if the first few days of January are down, the month will be too, and so will the year. There are minor variations of this myth—some claim it’s the first day alone that’s predictive. Most scoff at that, thinking it’s the first 3, 5, 10, 17, or some other random and arbitrary number (unable to see why if one day isn’t predictive, then 3, 5, 10, 17, or any other random number won’t be either). Some say it’s the first week, but then where does the holiday fall into that? And do four days make a week? All of this is nonsense.

Cognitive Errors Galore

There’s a whole mess of cognitive errors that happen with this and any other day-, month-, or season-related myth (like “Sell in May,” coming up in Bunk 25, or the supposed “Santa Claus” or “summer” rallies). First, almost never do you hear “so goes!” if January starts strong. Folks don’t say, “Phew! January was positive. No need to worry about the rest of the year!” No—folks who like this bunk usually use it to prop up bearish biases.
Second, this myth causes folks to reframe. If January is down and the year too, the “so goes” crowd claims victory (usually loudly). But if January is down and the year finishes up, the “so goes” crowd never issues a mea culpa.
Instead, they’ll claim, “Of course it doesn’t work every year. You must look at the long-term average.” They change the observation period for occurrences that don’t fit their pre-set notions. ...

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