Correlation and causation

As the new year started, many companies enter the period where the salary review process kicks in (yes, i include bonus evaluation into this as well). Having to prepare for this process, i decided to quickly create a visual aid to plea my case.

Exhibit 1: Stock price development at my former company (from the day i left, until today):

It is, I believe, evident that from the day i left the company, the stock price went down. I know, the stock price is not the only evidence of a company's performance, but it's not a bad one either.

One would rush to comment: "Correlation does not equal causation. The change in the stock price might be coming from countless variables, so you can't really claim that you leaving was the reason for the stock price change".

And i agree! What kind of data scientist works off one sample? Not me!

Exhibit 2: Stock price development at my current company (from the day i joined, until today):

Eat this sceptics. Do you see the difference in the slope? Do you see how the stock price has developed since the moment i joined?

One sample doesn't support "correlation equals causation". But 2? Hell yes!

I think i have definitively proven the value i add to my employers' business and how that is reflected in the stock price. All that remains now is to convince my boss that i deserve a raise of at least 30%, given that the stock went up by 37,5% since i was employed!

* I hope i won't have to explain to anyone that this is humorous post and that i don't actual claim that i was the sole influence for what happened with the stock price of these 2 companies. I also hope that i won't have to explain that this is in no way a post that reflects on how my current employer performs salary reviews.