Rational-choice theory is pervasive in legal theorizing. Most law and economics work assumes that human beings make decisions that are rational as to both their ends and means. Decisions are ends-rational if they are directed at goals that satisfy the person's utility function; decisions are means-rational if they adopt methods reasonably connected to achieving those goals. Institutionalist theory assumes that institutions are composed of actors pursuing their own rational ends by rational means and, further, that those institutions themselves can be said to have rational ends pursued by rational means. Most rational-choice theorizing in law is positive: Thinkers are using the theory as a stylized way of describing patterns of behavior or predicting expected behavior. Such theorizing can also be normative: Rationality of ends and means is an aspiration of human and institutional actors, and law can improve upon existing behavior through rules, procedures, and structures.