Weighing The Benefits And Costs Of DRM: Type I & Type II Errors
from the letting-in-too-much-or-not-enough dept
In statistics, there is the concept of “Type I errors” and “Type II errors,” with Type I errors representing “false positives” (reject, when should be allowed) and Type II errors representing “false negatives” (allowed, when should be rejected). After reading Simon Phipps’ recent excellent analysis of why DRM is “toxic to culture,” it occurred to me that one of the main areas of disagreement concerning DRM is over disagreements over the types of “errors” that DRM creates. Phipps compares subways in France and Germany — with the French subways involving a barrier which only rises if you insert a ticket. The idea here is, obviously, to prevent people from getting on the train without paying. In other words, they want to stop those who should not be in the set from riding the train. They’re trying to minimize Type II errors (get on the train when they shouldn’t be on the train). However, there are “costs.” The barriers cost money and need to be maintained. The technology may break at times, requiring repairs and blocking legitimate ticketholders from getting on their train (a Type I error). Law enforcement is needed to monitor the barriers to watch for “gate jumpers.”
In Germany, the system is much more open — there are no barriers, and no one may ever check your ticket. However, every so often tickets do get checked (somewhat randomly), at which point you would get fined for not having the proper ticket. This minimizes a different type of error — where someone who has paid and has a legitimate ticket has trouble getting through a gate. In other words, it’s minimizing Type I errors (blocking someone from getting on the train when they should be on the train). It also lowers many of those other costs (or takes them away entirely). Of course, the “cost” to such a system is that, obviously, some number will game the system and ride without paying (a Type II error).
I think one of the problems that people have in discussing DRM is that they only look at one type of error, and never bother to compare the two. As a result of that, those who support strong DRM tend to focus only on the “error” of letting people get a “free ride,” and ignore all of the collateral damage, as Phipps explains. Yet, when you compare the two, it’s difficult to see how one can argue that the “free ride” problem is worse than the problem of collateral damage from limiting legitimate uses. And that is why so many people have such problems with DRM. It’s not that we want a “free ride.” It’s that we worry about the costs associated with all of those collateral damage points.