16 ms·
How Cambridge Analytica’s Facebook targeting model really worked
- scottybowl 9y agoI'm excited for GDPR.. The hard part is going to be getting the truth out of these companies about the actual extent of the data they hold on us
- pavlov 9y agoThe EU should do a unionwide ad campaign pointing out the fact that the much-maligned eurocrats have actually been working for years to fix this very difficult problem that's only now becoming apparent to the wider public. The timing couldn't be better as GDPR goes into effect just after the Facebook/Cambridge scandal. Unfortunately all EU institutions are terrible at marketing. If they did an ad campaign, it would probably be a TV commercial showing Jean-Claude Juncker giving a speech with subtitles in 15 languages.
- rossdavidh 9y agoThat "hard part" is going to be more than just hard; I think the word you're looking for there is "impossible". They don't have any way of knowing what data Google, Facebook, Amazon, or any other company has. As this article does a credible job of explaining, you have to understand a fair amount about statistics (PCA) and machine learning to even know if if you were looking at it, and they won't know where to look for it. They have no enforcement mechanism in mind, and they passed a law anyway, which effectively means "you can't admit to having this", which will mean that the more willing a company is to lie, the bigger an advantage they will have over their competitors.
- rmateus 9y agoSure. But at least when they are actually whistleblowed (by people who "just" work for the company) there is a law which can be used to call to a court the theople who are legally accountable for the company
- daenz 9y agoAm I understanding this correctly? Facebook user data (likes/profile info) was scraped to produce low-dimension feature vectors for users (similar to word2vec). These feature vectors were then run through some ML model to predict...what exactly? Targetability for effective political ads?
- CiPHPerCoder 9y ago[ Deleted. Nothing I say on HN ever matters. Move along ]
- daenz 9y ago"What sort of lies" is pretty hand-wavy when it comes to labeling training data for a model. Are you summarizing from a source? I'm interested in the technical details of what happened.
- emodendroket 9y agoVery few "undecided" voters truly are; elections are won and lost by getting your supporters to go to the polls. So if you wanted to use scurrilous, fake news to help your candidate, you'd be better off sending stories that will get your supporters really fired up and eager to vote and get their friends to vote, not trying to persuade the practically nonexistent undecided demographic.
- rmateus 9y agoAre you able to specify the sources based on which you are supporting these claims, namely that elections are not not decided by "undecided" voters but rather by pushing your supporters to the election polls?
- emodendroket 9y agoI thought this was common enough knowledge not to want citations, but I think you will find these satisfactory. http://www.stat.columbia.edu/~gelman/research/unpublished/swing_voters.pdf http://www.stat.columbia.edu/~gelman/research/unpublished/sw... https://www.politico.com/magazine/story/2014/01/independent-voters-partisans-in-the-closet-101931 https://www.politico.com/magazine/story/2014/01/independent-... https://www.thenation.com/article/what-everyone-gets-wrong-about-independent-voters/ https://www.thenation.com/article/what-everyone-gets-wrong-a... The last piece has a short summary of the salient point: > In fact, according to an analysis of voting patterns conducted by Michigan State University political scientist Corwin Smidt, those who identify as independents today are more stable in their support for one or the other party than were “strong partisans” back in the 1970s. According to Dan Hopkins, a professor of government at the University of Pennsylvania, “independents who lean toward the Democrats are less likely to back GOP candidates than are weak Democrats.” > While most independents vote like partisans, on average they’re slightly more likely to just stay home in November. “Typically independents are less active and less engaged in politics than are strong partisans,” says Smidt. > [...] > The conventional wisdom holds that the parties need independents to win general elections, but the reality is that they’re increasingly devoting their resources to getting their own voters—including their “closet partisans”—out to the polls rather than trying to sway the dwindling number of genuine swing voters. “We’ve seen a huge increase in technology and the ability to turn out the vote,” says Smidt. “So in terms of a cost-benefit analysis, the parties and candidates see that it’s much easier to turn out people who agree with them than it is to change someone’s mind. And then there’s also the question of how many of us are even open to changing our minds.”
- godelski 9y ago> has revealed that his method worked much like the one Netflix uses to recommend movies. I'm not sure this is the model you want to emulate. The suggestions are terrible and continually getting worse.
- rjurney 9y agoIt's a hard problem but Netflix's model represents the state of the art in machine learning for recommendations. Still scared of the singularity? :)
- nicoburns 9y agoReally? Because in terms of actual usefulness, I find youtube's suggestions to better...
- godelski 9y agoYoutube does better than Netflix for me, but they still suggest stuff that I have already watched. Sometimes stuff I literally watched an hour ago. And I watched one Joe Rogan episode and it will not stop suggesting it to me but fails to notify me on things that I watch every episode on; like 3Blue1Brown, Robert Miles, or Rare Earth.
- factsaresacred 9y agoSpotify is king IMO. Their 'discover weekly' playlist turns up gems every time. But that's because they dive into other user playlists that contain the same music you play. Pretty simple. I assume Youtube do somthing similar. If Netflix had playlists or a 'want to watch' feature I bet their recommendations would improve.
- scoggs 9y agoI tend to agree with you. The only thing I dislike about it is when I happen to open a link I'll randomly be sent or notice in an article that's something unlike what I normally enjoy or something I close right away and then for the next few days, or until I watch a bunch more of what I usually enjoy, the entire suggestion list is only things to do with that one random link.
- lordnacho 9y agoFinally, I was waiting for someone to talk about the model itself. It makes sense that SVD or something like it (PCA, co-occurrence, etc) would be used. But I also wonder what exactly you are going to do with the predictions. What exactly do you show to someone to make them more likely to go and vote if they are inclined to vote your way, or make them stay at home otherwise? Is there evidence that whatever you're showing actually works? Or do you try to change people's minds? What do you do? Knowing how the state of things -in this case, people's voting inclinations- is not the same as knowing what to do, ie a strategy. I don't know how effective it is, I'd like to learn more. But I smell the possibility that these CA type firms are simply selling snakeoil to desperate political activists.
- tomrod 9y ago> What exactly do you show to someone to make them more likely to go and vote if they are inclined to vote your way, or make them stay at home otherwise? Qualitatively: show things that get them angry. Quantitatively: test and control pop splits.
- mattmanser 9y agoHow do you test anything? There's only one vote, you can't iterate.
- metaobject 9y agoMaybe with polling?
- emodendroket 9y agoI am really puzzled by the Cambridge Analytica scandal. It's not particularly savory, but is there something happening here that it wasn't basically already known about how Facebook worked? By the protests of their own executive, the system was working as designed, and at worst Cambridge Analytica misled them about how they intended to use the data, right? There was no actual security breach here, as far as I can understand it.
- jacquesm 9y agoThere doesn't have to be a security breach for it to be a very bad example of using data collected in one way for a completely different purpose. It violates the 'lawful basis for processing' part of privacy legislation.
- hueving 9y agoWhich US legislation?
- jacquesm 9y agoThat app collected data on many more than just US residents so more than just US legislation applies. This is one of those pesky little problems of doing stuff 'on the internet', especially when you start doing stuff that is purposefully or accidentally illegal. Besides that they apparently also used similar trickery in their consultancy for the Brexit side. https://www.theguardian.com/politics/2018/mar/26/pressure-grows-on-pm-over-brexit-cambridge-analytica-scandal-theresa-may https://www.theguardian.com/politics/2018/mar/26/pressure-gr... This is far from over. https://www.theguardian.com/commentisfree/2018/mar/23/plenty-more-like-cambridge-analytica-data-facebook https://www.theguardian.com/commentisfree/2018/mar/23/plenty...
- pjc50 9y agoCambridge Analytica are in the UK. Which is why the Information Commissioner got a warrant to search their offices.
- ikeyany 9y ago
- spitfire 9y agoWhen talk about CA first emerged on HN before the election some posters found the original papers referred to. They were looking at pictures in the story and zoomed in to find the titles. I cannot find those posts for the life of me again. Not suggesting anything nefarious here, I just can't find them. Does anyone have a link to those early conversations or make copies of the papers? I made copies earlier but deleted them before I put them into my papers archive.
- erikpukinskis 9y agoHere are some leads: https://news.ycombinator.com/item?id=14486365 https://news.ycombinator.com/item?id=14486365 https://news.ycombinator.com/item?id=14393991 https://news.ycombinator.com/item?id=14393991 https://news.ycombinator.com/item?id=14330547 https://news.ycombinator.com/item?id=14330547 https://news.ycombinator.com/item?id=14284502 https://news.ycombinator.com/item?id=14284502 https://news.ycombinator.com/item?id=13939814 https://news.ycombinator.com/item?id=13939814 And the query: https://hn.algolia.com/?query=mercer&sort=byPopularity&prefix&page=1&dateRange=custom&type=comment&dateStart=1470528000&dateEnd=1506816000 https://hn.algolia.com/?query=mercer&sort=byPopularity&prefi...
- spitfire 9y agoNo none of those are it. I believe it was before the elction that the article came out. There was a picture of someone reading the paper CA was supposedly based upon in the article. Someone zoomed in and found the paper. I'll keep looking.
- etiam 9y agoSpoiler warning. Article punchline ahead. "The whole point of a dimension reduction model is to mathematically represent the data in simpler form. It’s as if Cambridge Analytica took a very high-resolution photograph, resized it to be smaller, and then deleted the original. The photo still exists — and as long as Cambridge Analytica’s models exist, the data effectively does too." That's an eloquent piece of explanation of a very important point. And apropos the discussion about privacy legislation, it's also going to be a very interesting point. Will the Cambridge Analyticas of the world be able to claim they have held on to no personal data, when strictly speaking the raw data has indeed been deleted after being used to create a derivative work that can for all important purposes be used to recreate the original? Assuming I find out I'm being profiled and demand to have my data removed, will society grant me rights to have derivative forms removed or adjusted too? I'm somewhat pessimistic that legal hairsplitting about matters like these will make enforcement very difficult.
- autokad 9y ago> "will society grant me rights to have derivative forms removed or adjusted too? " I am in favor of no. Imagine I build a gender classification model off public tweets, and then you later delete your twitter account and demand my model not be used because it was trained off 'your data'. I am in the camp that so long as the data isn't traceable back to you specifically, then don't put any information out there you are not OK with sticking around.
- salty_biscuits 9y agoI guess the question is what are you trying to protect? The model is fundamentally lossy as it is a rank reduction method so your original data is gone (i.e. no one would be able to accuse you of liking a particular controversial post, just that you are likely to like that post). So it sort of has the differential privacy thing going on. I guess it is another question as to if such models should be built at all. I think the fidelity of the models will answer that in time, if they work really well it is scary, if they are poor models they will cease to be used. I suspect that it will be in the middle and highly sensitive to the quality of the original data and the quality of the implementation like all ml applications.
- 9y ago
- tunesmith 9y agoIsn't the accuracy of the predictions kind of orthogonal to the fact that they were basically lying in their attempts to change behavior? Using lies to convince someone to do something is going to be more effective than using truth, if that "something" is not in accordance with the truth. The comparison with netflix really breaks down there. You're not going to be able to convince me that I liked Crash, so recommendations based off of that aren't going to be very useful to me. But if you reinforce my false belief that Obama and Soros are gonna use the deep state to invoke Sharia Law on the 2nd amendment, then that might better convince me to vote for so and so.
- willart4food 9y agoarchived for future reference http://archive.is/dMIcN http://archive.is/dMIcN
- vcdimension 9y agoThis is the standard way of analysing this kind of data, and I'd be very surprised if the Obama campaign didn't use the same or very similar methods with the facebook data they obtained. The only difference is that Cambridge Analytica managed to obtain much more data over a wider demographic.
- soared 9y agoVery interesting article but I wish it went one step further. Why does it matter that cambridge analytica knew a user's big five or that they were an old, uneducated republican? How was this (inferred) data used? I assume they wrote/created different ads for different sets of users... but how many segments did they have? Did their graphic designer build 500 different ads, or was text/images dynamically inserted based on these variables? How did they figure out which message would resonate with each segment? How did they test something like this, with so many potential variables? Was this knowledge used only on facebook, or across all digital channels? Was it implemented in non-digital channels as well? I'd kill to have access to their campaign set ups.
- aluhut 9y agoI wonder if you learned something since your blatant failure last week where you gave all that trust into facebooks hands, and praised advertisements, one day before they've blown up.
- soared 9y agoOh, I forgot you were the one who called me mind rapist for working in advertising. I'm tempted to do an AMA here so people can hear the perspective of an insider (not to sway opinions necessarily, but to quell some misconceptions and understand how we got here/how things actually work)
- aluhut 9y agoOh come on, you are a failed video platform guy who got kicked out of YC startup school (I got that from your data out there/here scared? Probably not, because we are giving it all away...don't we?). Last week you have already shown that you seem to have no idea what you are talking about and you ran away when you got cornered. One day before my main point (that one about data) became reality for everybody. The day when your ignorance about people giving their data to advertisers has shown their evil outcome. I wanted to hear from you if you feel anything about it now. Regret anything? A slight feeling of guild or ANYTHING there? Did you learn something? It seems not. Now you want to have an AMA. What for? You didn't know that things like canvas exist a week ago. Now you want to tell us about your experience? Or is this just advertising for yourself? PS. Seeing that the only thing you could remember was the advertising for my post (mind rape), shows that I'm a better advertiser then you.
- cosmic_ape 9y agoBesides the data, its interesting how the actual targeting was performed. Does facebook provide an option to show a particular given ad to a particular given user? Or is it possible to select a group of people with a given set of likes? How fine-grained is facebook's audience selection mechanism for ads? Or was the targeting performed by creating fake groups, befriending people?
- albertTJames 9y agoYeah yeah, they only tried SVD on a multimillion dollar dataset. Psy-ops, netflix, same deal, what is all the fuss about! Strange that a research scientist is released of his NDA a couple of days after channel 4 documentary.
- katebrooks 9y agoAnd we can't blame the companies because we agreed our data to be monitored when we installed the apps and granted permissions. Facebook and Google has taken so much of our data and knows more about our behavior than we ourselves. Even if I demand my data to be removed I don't know if they will 'actually' delete it.
- gleglegle 9y agoWho says we can't blame them?
- rhemgla_corp 9y agoHere is an interesting layout of the targeting model for those of you who want to know more: https://2no.co/1QyvB6 https://2no.co/1QyvB6