December 19, 2021

Correlation and Causation Symbolsgood shorthand against bad mental shortcuts

I accidentally did myself a very good turn when it comes to taking notes. Using x→y for “x causes y” or “x implies y” but x∝y for “x correlates with y” or “x is proportional to y” helps remind me to distinguish causation and correlation.

Symbol Unicode HTML Entity Vim Digraph
U+9192 → Ctrl+K ->
U+2190 &larr; Ctrl+K <-
U+221D &prop; Ctrl+K 0(

Inverse correlations can also be expressed with ∝, as correlations to the reciprocal: x∝⅟y, x∝1/y, x∝y-1, or x∝y¹.

Symbol Unicode HTML Entity Vim Digraph
U+215F
¹ U+00B9 &sup1; Ctrl+K 1S

I recall using for therefore and for because in grade school. I believe I saw those first in chemistry class. The arrows used in computer science and formal logic eventually won out in my personal shorthand.

Symbol Unicode HTML Entity Vim Digraph
U+2234 &therefore; Ctrl+K .:
U+2235 &because; Ctrl+K :.

It probably helps that legible lines are easier and faster to write by hand than dots. And that the causal directions of and are obvious.

Your thoughts and feedback are always welcome by e-mail.

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