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` |
`←` |
`Ctrl+K <-` |

∝ | `U+221D` |
`∝` |
`Ctrl+K 0(` |

*Inverse* correlations can also be expressed with ∝, as correlations to the reciprocal: `x∝⅟y`

, `x∝1/y`

, `x∝y`

, or ^{-1}`x∝y¹`

.

Symbol | Unicode | HTML Entity | Vim Digraph |
---|---|---|---|

⅟ | `U+215F` |
||

¹ | `U+00B9` |
`¹` |
`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` |
`∴` |
`Ctrl+K .:` |

∵ | `U+2235` |
`∵` |
`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.