Legal Theory Lexicon 026: Rules, Standards, and Principles

Introduction Early on in law school, law students begin to realize that legal norms are not all cut from the same cloth. Some rules provide "bright lines," others "fuzzy lines," and yet others, no lines at all. The "reasonable person" test in tort law constrains in a very different way than does the rule against perpetuities in property. That is, legal norms differ in extent to which they constrain those who are charged with applying them.
We can slice and dice legal norms in various ways. In this post, we will investigate the idea that legal norms can be sorted into three general classes: rules, standards, and principles. Let's stipulate to the following definitions to get the discussion off the ground:
• Rules are the most constraining and rigid. Once a rule has been interpreted and the facts have been found, then the application of the rule to the facts decides the issue to which it is relevant.
  
• Standards provide an intermediate level of constraint. Standards guide decisions but provide a greater range of choice or discretion; for example, a standard may provide a framework for balancing several factors.
  
• Principles are even less constraining. Principles provide mandatory considerations for judges. Whereas, standards identify an exhaustive set of considerations for adjudication or policy making, a principle identifies a nonexhaustive set, leaving open the possibility that other considerations may be relevant to the decision.
This post provides an introduction to rules, standards, and principles for law students (especially first-year law students) with an interest in legal theory.
Rules Although the phrase "legal rule" can be used in a broad sense, to refer to all legal norms, whether they be case in the form of a bright-line rule, a standard that in the form of a balancing test, or even an abstract principle, there is also a narrower sense of "rule" that distinguishes rules from standards and principles.
Rules themselves vary--let's use hard and soft to refer to the poles of a continuum. A rule is harder if both the conditions for its application and the consequences that follow are defined by bright-line distinctions that admit of easy application. The rule that disqualifies persons who are not 35 years of age is quite hard or rigid. Rules become softer as they criterion for the application and/or the consequences to which they lead become fuzzier. If the constitution had limited the presidency to "adults," then there could have been cases in which the question whether a particular candidate was unclear. Twelve year olds are clearly not adults but twenty-five year olds clearly are. In between, the necessity of drawing a somewhat arbitrary line makes the "adult" rule relatively softer than the "35-year old" rule.
Standards Standards are less constraining than even "soft" rules. Whereas a rule defines a triggering condition and a consequence, a standard may define a set of relevant considerations and options. One familiar example of a standard is provided by the fairness component of the International Shoe test for personal jurisdiction. That test requires a court to find that a state's assertion of personal jurisdiction violates the Due Process Clause on the basis of a give factor balancing test, which refers to the defendant's interest, the plaintiff's interest, the interest of the forum, judicial efficiency and economy, and substantive policy concerns.
Like rules, standards themselves vary in their capacity to guide and constrain the decision-making process. Some standards give the decision maker substantial guidance, by specifying relatively specific and concrete factors the decision maker should consider and the relative weight or importance of those factors. Other standards are much more open ended, requiring consideration of factors that are general and abstract. Standards that refer to "all the circumstances," "the interests of justice," or "equitable considerations" are particularly soft. Standards that require the evaluation of "cost to the defendant" or "serious invasions of privacy" are relatively harder, providing greater constraint and guidance.
By way of illustration, consider eligibility for the presidency once again. A rule based approach might limit eligibility to persons of a certain age or to "adults." A standard might specify that the only persons who are "sufficiently mature" may occupy the office of President. This standard is relatively open-ended, and it might disqualify some sixty-year olds from the presidency but allow some 20 year olds to serve.
Principles Principles are quite different from both rules and standards--at least on the basis of the definitions that we are using. Both rules and standards provide a framework that is, in theory, sufficient for resolving a particular issue in a legal dispute. But as we are using the term, a "principle" only provides guidance for the interpretation or application of a rule or standard. Principles by themselves do not resolve legal issues.
This sense of principle is illustrated by Ronald Dworkin's example of the principle that no one should be allowed to profit from their own wrong, drawn from the case of Riggs v. Palmer, 22 N.E. 188 (N.Y. 1889). In that case, the statute of wills would have allowed a murderer to inherit from his victim, but the New York Court of Appeals concluded that the statute should be given an equitable interpretation in light of the common law principle against wrong doers profiting from their wrongs. This principle is not a rule: the law does permit wrong doers to profit from their wrongs in a variety of circumstances. Rather, this general and abstract principle provided guidance in the interpretation and construction of a rule--in Riggs, the rule provided by the statute of wills. (This example is drawn from Ronald Dworkin's famous essay Hard Cases.)
The Pros and Cons of Rules, Standards, and Principles What are the pros and cons of rules, standards, and principles? When you have identified a candidate legal norm, when should you argue that the norm should be formulated as a rule, a standard, or a principle? In his famous 1985 article, Pierre Schlag provided this example:
In one torts casebook, for instance, Oliver Wendell Holmes and Benjamin Cardozo find themselves on opposite sides of a railroad crossing dispute. They disagree about what standard of conduct should define the obligations of a driver who comes to an unguarded railroad crossing. Holmes offers a rule: The driver must stop and look. Cardozo rejects the rule and instead offers a standard: The driver must act with reasonable caution. Which is the preferable approach? Holmes suggests that the requirements of due care at railroad crossings are clear and, therefore, it is appropriate to crystallize these obligations into a simple rule of law. Cardozo counters with scenarios in which it would be neither wise nor prudent for a driver to stop and look. Holmes might well have answered that Cardozo's scenarios are exceptions and that exceptions prove the rule. Indeed, Holmes might have parried by suggesting that the definition of a standard of conduct by means of a legal rule is predictable and certain, whereas standards and juries are not. This dispute could go on for quite some time.
Here are some basic ideas about the appropriateness of rules, standards, and principles:
• Predictability and certainty. If your goal is ex ante predictability and certainty, then rules are usually the way to go. Predictability and certainty are particularly important when the law seeks to guide future conduct. For example, if we want to deter particular forms of conduct, we may do better to define the conduct in a rule (or in a set of rules) that would enable those who engage in the conduct to clearly see that the proscribed conduct is forbidden. Standards provide less guidance, and principles, almost no guidance at all.
  Fairness and sensitivity. On the other hand, if our goal is to insure ex post fairness, then standards may be the way to go. Standards permit flexibility and the consideration of mitigating circumstances. Rigid rules are likely to lead to unfairness in particular cases, because it may be difficult to define in advance all of the circumstances which should count as exceptions to the rule.
  The job of principles. Principles seem best suited for another sort of legal task. Principles cut across doctrinal fields. The same principle--one may not benefit from one's own wrong, for example--may apply in torts, contracts, and the law of wills. Thus, principles are particularly well suited to give legal form to concerns which operate in a wide variety of particular contexts.
Conclusion Legal theorists need to be able to identify rules, standards, and principles, and more importantly, to be able to argue the pros and cons of formulating legal norms in these standard forms. The main goal of this post has been to enable you to distinguish a rule from a standard and to see that principles operate in a different way than either rules or principles. I also hope that the post has provided you with some tools that will enable you to make arguments like: “this rule would better be reformulated as a standard, because . . ." And arguments, like, “that legal norm really isn't a standard at all, it is better described as a principle.” I've provided some additional references, for those who want to pursue these ideas further.
References
Baird & Weisberg, Rules, Standards, and the Battle of the Forms: A Reassessment of § 2-207, 68 Virginia Law Review 1217 (1982).
Ronald Dworkin, Hard Cases in Taking Rights Seriously (1977).
Herbert Hart & Albert Sacks, The Legal Process (unpublished manuscript tent. ed. 1958).
Duncan Kennedy, Form and Substance in Private Law Adjudication, 89 Harvard Law Review 1685 (1976).

• Pierre J. Schlag, Rules and Standards, 33 UCLA L. Rev. 379 (1985).