[hildea]

Originally Posted by Dopedangel

Just by data mining target has had the capability to predict that a teenage girl was pregnant even before her parents in 2010

I was at a conference about big data where this anecdote was discussed. Even if it's true, we don't know:

• How many customers who got pregnancy-related ads without being pregnant
• How many customers who were pregnant who didn't get those ads

So, at best we know that one pregnant customer got those ads, but that might be just random luck.

Another problem with using big data is that they can strenghten existing predudices. For instance say two different demographic groups use drugs equally much, but one of them is stopped and searched in random checks more often (because of predudice in the police). Then your data will tell you, quite correctly, that members of group A are more likely to be arrested for drug crimes than group B. If you use this to decide how to prioritize which groups to check more often in the future, you are making policing even more predudiced, and believing you are basing it on objective data.