Re:Machine Learning: The High-Interest Credit Card of Techni...
by jongraehl on Saturday December 20, 2014 @03:15PM
(#8777775)
"We made a great prediction that didn't pan out because others also acted on the same prediction" or "the future just didn't turn out like the past in that particular data-mined aspect and we don't know why"? I know which story I'd want to tell were it my unprofitable system.
Some of the other problems listed are new, coming from taking what used to be research techniques and putting them into production programs. Those are more like ordinary big system problems, such as configuration management. The article points out, though, that your huge training set is now part of your configuration.
Then there's the problem of systems assigning excessive significance to features which happen to work but are really irrelevant. Those image recognition demos on HN last week illustrated this problem. At least there, though, there's a way to visualize what's happening. For many ML systems, humans have no clue what the system is actually recognizing. If your ML algorithm has locked onto the wrong features, it can become drastically wrong due to a minor change in the data. I saw an example of this in a web spam filter that was doing fairly well, working on 4-character sequences taken from web pages. It was actually recognizing specific code text used by one ad service. The page content seen by humans was totally irrelevant.