can be found across the full range of scientific inquiry. Throughout this chapter we provide examples from a variety of domains—in political science, geophysics, and education—to demonstrate this shared nature. Although there is no universally accepted description of the elements of scientific inquiry, we have found it convenient to describe the scientific process in terms of six interrelated, but not necessarily ordered,¹ principles of inquiry:

• Pose significant questions that can be investigated empirically.

• Link research to relevant theory.

• Use methods that permit direct investigation of the question.

• Provide a coherent and explicit chain of reasoning.

• Replicate and generalize across studies.

• Disclose research to encourage professional scrutiny and critique.

We choose the phrase “guiding principles” deliberately to emphasize the vital point that they guide, but do not provide an algorithm for, scientific inquiry. Rather, the guiding principles for scientific investigations provide a framework indicating how inferences are, in general, to be supported (or refuted) by a core of interdependent processes, tools, and practices. Although any single scientific study may not fulfill all the principles—for example, an initial study in a line of inquiry will not have been replicated independently—a strong line of research is likely to do so (e.g., see Chapter 2).

We also view the guiding principles as constituting a code of conduct that includes notions of ethical behavior. In a sense, guiding principles operate like norms in a community, in this case a community of scientists; they are expectations for how scientific research will be conducted. Ideally, individual scientists internalize these norms, and the community monitors them. According to our analysis these principles of science are common to systematic study in such disciplines as astrophysics, political science, and economics, as well as to more applied fields such as medicine, agriculture, and education. The principles emphasize objectivity, rigorous thinking, open-mindedness, and honest and thorough reporting. Numerous scholars