The Rule-Standard Distinction vs. The Smooth-Bumpy Distinction

If you've been following my posts on the smooth-bumpy distinction, you may be wondering how this distinction relates to the rule-standard distinction. The rule-standard distinction is iconically illustrated by prohibitions on speeding. A prohibition on “driving over sixty-five miles per hour” is a rule: it draws a bright line and affords little discretion to those who interpret it. We may choose a rule-based prohibition on speeding because it makes clear what conduct is prohibited and is easy to apply. The rule does not fit perfectly, however, with the overarching norm to drive safely, since there are conditions under which people should drive slower than the speed limit and conditions under which it would actually be quite safe to drive faster. By contrast, a law prohibiting “driving at an unsafe speed” is phrased as a standard. It reflects the overarching norm that should govern driver conduct but gives less concrete guidance than does the rule-based version and requires more discretion to apply.

The rule-standard distinction helps us formulate a threshold test to distinguish permitted and prohibited conduct. It says nothing, however, about whether the penalty associated with crossing the threshold kicks in gradually or dramatically. Assume, for example, that in response to dangerous driving, legislators institute a law with a flat $100 fine for violations. Since crossing the threshold costs $100 no matter how fast you were driving, the law has a bumpy relationship between excess speed and punishment. Notice that the law is bumpy no matter whether the threshold is formulated as a rule (a speed limit) or as a standard (a dangerousness prohibition). We look at the variable that matters to us (be it speed or level of safety) and convert it into one of two outputs. You are either subject to a $100 fine or to no penalty at all. The penalty is bumpy because, after the legal threshold is crossed, the law is insensitive to how much a person speeds or how dangerously he drives.

By making the penalty more flexible, we could smooth it out. Rather than imposing a fixed $100 fine for driving above the speed limit, we could impose a $10 fine for each mile-per-hour one drives above the speed limit. Similarly, we could smooth application of the standard. Rather than imposing a fixed $100 fine for driving at an unsafe speed, we could impose a fine proportional to the recklessness of the driver given particular road conditions. Hence, whether a threshold is framed as a rule or a standard, the penalty for violation can be either smooth or bumpy. The smooth-bumpy distinction simply captures a different feature of law than does the rule-standard distinction.

It is true that penalties can themselves be thought of as rules or standards. The penalty for speeding could be posed as a rule (“$100”) or as a standard (“a fine in such amount that the offender gets what he deserves”). But rules and standards still vary along a dimension of smoothness. For example, the penalty for speeding could be a $100 fixed fine or a $10 fine for each mile-per-hour driven above the limit. Both penalties are equally rule-like. They are easy to apply and leave judges with little discretion. Still, the fixed fine is very bumpy while the fine pegged to speed is rather smooth. Thus, no matter whether we use rules or standards, we still need to separately consider the smoothness of the law.

Consider the difference between contributory and comparative negligence. Contributory negligence is bumpy because if a plaintiff’s negligence contributes to his injury, he cannot recover from the defendant at all. Though a plaintiff’s negligence is a matter of degree, it gets converted to a binary output: the plaintiff was either contributorily negligent or not. By contrast, comparative negligence is smooth with respect to a plaintiff’s negligence because, in its purest form, the extent of a plaintiff’s negligence determines the extent to which his award is reduced. However, the choice between contributory and comparative negligence is principally a substantive question about the nature of tort compensation—namely, whether a plaintiff’s negligence should cause a smooth or bumpy reduction to his award for damages—not a debate about rules and standards. 

There are, of course, certain similarities between rules and standards on the one hand and smooth and bumpy laws on the other. For example, standards generally do a better job of capturing underlying normative concerns than do rules. Similarly, I claim, smooth laws often do a better job of capturing underlying normative concerns than do bumpy laws. Also, rules are usually cheaper to administer than standards, just as bumpy laws, are usually cheaper to administer than smooth laws. But superficial similarities aside, we are addressing two different features of the law. Moving right may take you east, while moving left may take you west. But east and west and left and right draw importantly different distinctions.

(This post is adapted from Smooth and Bumpy Laws, 102 Calif. L. Rev. 655 (2014).)