There are millions of lines of code existent. There are thousands added. Your prior for it being Elon's addition should be something like 10,000/1,000,000 or roughly 1/100. The prior that it wasn't Elon's change is going to be something like 99/100.
When you add the additional information that Elon wants the code removed, but existing Twitter engineers think it appropriate to keep this actually increases the probability of it being added by the existing Twitter engineers and decreases the probability it was added due to Elon.
Obviously, these are rough numbers, but hopefully seeing any numbers at all helps you to get an intuition for the math.
Why is lines of code the appropriate input here? Here's a different computation that is at least as plausible:
There are hundreds of millions of users. Let's say 300M. Only a single one is special-cased in this code: the narcisistic CEO who reportedly went ballistic when his engagement metrics went down. The prior that it's a change done in response to his demands is 299999999/300000000.
(But of course it was added by existing Twitter engineers. The odds of Musk being able to actually commit code to their repository are zero. Even if he had the permissions, the man simply does not have the technical acumen to make even a trivial change.)
I think you are right, my estimate is much much too low.
I'll explain my mistake and why I made it.
I think I thought to use the estimate I did because Elon claimed he didn't know. The prior probability of not knowing something in a code base with millions of lines is very high, but contingent on his involvement in the change the prior that he is aware of it is much higher. So I started the estimate attempt with the probability that I thought better predicted the production of evidence claiming he didn't know.
Your point does raise my estimate substantially, but I think it probably raises it less than you would expect. I don't agree with your 1/300M prior, because I'm aware that hot users get special treatment. I've seen Elon's account thrown around in interview-style questions about hot users before and used as an example of a hot account that needs special treatment. This is something I've witnessed, but it wasn't contingent on Twitter being acquired and it happened prior to Twitter being acquired.
I also don't particularly assign high odds to wanting it, based on the evidence that he claimed to not want it implicitly by wanting it removed. I don't think it seems appropriate to get to near certain probability the he wanted it with the evidence being that he stated that he didn't want it. In my view there isn't a compelling reason for him to lie about this. He owns Twitter, so if he wanted them to have his account monitored that would be a reasonable thing well within his authority. If he wanted it, he doesn't need to pretend to not want it in order to appease someone.
It does seem to me that the odds that the change was added in response to someone thinking he wanted it is much higher than 1%.
> I don't agree with your 1/300M prior, because I'm aware that hot users get special treatment.
That's absolutely fair, and 1/300M was a reductio ad absurdum rather than a serious proposal. Not all users are equal, just like not all lines of code are equal :)
I have a few issues with the "hot user" theory, but they all boil down to the same point: no matter what the use case, you'd never want to do this with a single static user.
Does your infra require special-casing for accounts with more than 100M followers? That should be a flag in the account properties that gets flipped manually or automatically: if these users cause infra problems, you really don't want to be making code changes + full rollouts whenever a new user becomes hot.
Is this just a guard-rail metric, to make sure there's not some bug specifically affecting hot users that tanks their engagement? You'd want a much larger static set than a single account just to ensure there's a large enough number/variety of tweets to compute metrics from. A single user might take a break for a week, or might only be posting very specific kind of content for an extended period of time.
In any case, even if you chose to do this with a single user rather than a set of users, why would Musk be the obvious single choice? He wasn't the most followed Twitter account until two days ago. A year ago there must have been at least a couple of dozen accounts roughly as notable as Musk. The odds of him having been chosen as the special case still would not be very high.
> In my view there isn't a compelling reason for him to lie about this.
The reason to lie about this is that it makes him appear weak, needy, and a target of even more mockery. Given the purchase of Twitter seems to have been a vanity project, having this be exposed and leaving it in goes directly against his apparent goal.
> The reason to lie about this is that it makes him appear weak, needy, and a target of even more mockery. Given the purchase of Twitter seems to have been a vanity project, having this be exposed and leaving it in goes directly against his apparent goal.
I think it only makes sense to think like you are if you've adopted equilibrium assumptions; if you haven't then I find this sort of reasoning to be a conjunction fallacy causing an epistemic closure.
JoshCole is doing a computation to arrive at the conclusion that there's a <1% chance that this code was added after Musk bought Twitter. I'm using the same methodology with at least equally plausible inputs to arrive at there being a >>99% chance of it.
How is that a nitpick? They're diametrically opposite results.
I'm JoshCole and I didn't find your reply to be a nitpick; you are right that the probability ought to be higher than 1%. My calculation was simplistic and I felt it was prudent to arrive at low probability, because I think probability of wanting something given claim of wanting it removed should probably not be anywhere near close to certain. My estimate isn't 1% though. It was just a short thing to share that gave an intuition for why it might be reasonable to assume he didn't know or want it.
In my opinion if you really care about this topic the right thing to do is ask someone at Twitter when the change was made. Getting more information would make us converge on the true estimate faster than arguing the odds IMO. Feel free to update me with the results if you do end up doing that so I can adjust my beliefs accordingly. I'm not going to try to gain this information, because I don't think the question matters much.
