As a historian of science education, I was excited to see the article “A Brief History of Physics Education in the United States” in a recent issue of this journal by Meltzer and Otero [Am. J. Phys. 83(5), 447–458 (2015)]. The history of science education is an area of growing interest in a number of disciplinary fields and for good reason; the more we can learn about past educational practice, the more we can begin to develop a greater understanding of why we teach science and what we hope to accomplish through such teaching. But as I began reading, it became clear to me that the authors had produced a history of physics education only in part—a key element of what makes scholarship was missing.

The problem was that the authors of this history (which covers the years from 1860 through 2014) left out nearly all of the secondary source material, citing work written almost exclusively by physicists and physics educators on the subject of how best to teach the subject.

Let me explain. In any empirical research, there are data (the evidence that is reasoned about or made sense of) and there is the work that other researchers have published on that topic. The other work is often included in the introduction of a research paper or in a section called “background” or “theoretical framework.” Authors cite this past work in order to set the stage for the original contribution that they are hoping to bring to the larger community; the goal is to highlight what others have done and then to use this to show how their findings (based on the data they have collected) extend that work in some new and significant way.

History is an empirical field of research as well. That is, researchers (historians in this case) collect and make sense of data and do so in light of what other historians have written in the past. Data for historians are sometimes referred to as “primary source material,” which includes published and sometimes unpublished articles, documents, and correspondence from the time period under study. The background or framework part of any piece of historical scholarship is built from what's called the “secondary literature,” and historians frequently will “set up” the narrative they are advancing (the history being told) by referring to this secondary literature (what other historians have written on the topic in question). Such references are sometimes limited to the footnotes in order not to disrupt the flow of the story, but are always present to provide the scholarly context for the work, to acknowledge the research that others have done in finding and identifying the primary source material, and/or to give readers directions to where they might find additional information or interpretations of the subject at hand.

In Meltzer and Otero's brief history of physics education, this secondary material—the material that acknowledges the work of others and that allows readers to see what is being offered as new and significant—is simply missing (with the exception of two references, to the work of DeBoer and Kevles). Readers should have found references to scholars such as Kathryn Olesko, Steven C. Turner, Albert Moyer, Sidney Rosen, John Heffron, Larry Owens, Michelle Hoffman, and Peter Dow among many others.

Now one might argue that readers—particularly those with research training in physics who presumably read this journal—have no need for the secondary literature, that they need and would only see as legitimate references to the writings of the physicists and physics educators as they were published from decade to decade over the course of the last 150 years, the “raw data” so to speak. But this would be analogous to a physics education researcher attempting to publish a study on student understanding of force, for example, that included only the raw data from the student interviews, surveys, or test results without any reference to work by other researchers who have done prior studies on student understanding of the force concept; without acknowledging that past work, it would be to pretend that such a study was being done for the very first time. If a paper like this were submitted to a research journal, it would surely be sent back with instructions from the editor to “situate the work in the existing literature on the topic.” Indeed, the author guidelines for this very journal stipulate, “articles in AJP must adequately recognize prior work, whether that work was published in AJP or elsewhere.”

The inclusion of theoretical frameworks or background literature or, in the case of historical research, the secondary literature is not an “option” that can be chosen depending on who is thought to be the audience. It is an essential part of what makes scholarship legitimate; it's how we know that we can trust the work that researchers have done. The norms of historical research are, in this sense, no different than the norms of any kind of empirical research, and I would urge physicists and physics educators who decide to try their hand at such work to recognize their obligation to adopt the standard practices of the field.