made up of constituent parts. these parts are often referred to as either rhetorical concepts or rhetorical principles. rhetorical concepts can be seen as tools of the trade that allow rhetoricians to effectively communicate in a way that is most likely to persuade readers and audiences of the messages and meanings intended by the rhetorician. rhetorical concepts are an important part of what makes an argument persuasive, and all effective arguments inherently contain them. rhetorical concepts help rhetoricians convey information that would otherwise be unascertainable by the audience, which is especially important for topics that carry heavy implications, such as the complications that often follow complex medical and health needs. figures of speech figures of speech are a type of figurative language that often convey specialized meaning not based on the literal meaning of the words that make up the figure. often providing emphasis, freshness of expression, or clarity, they can be used to explain complex, unknown topics to readers and audiences in a way that makes them easier for the reader to understand. metaphor and analogy metaphor and analogy are important in scientific communication because they make new ideas understandable to both expert and nonexpert audiences. disease, for example, which is difficult to comprehend on both large and microbiological scales, is often communicated through metaphor and analogy. when a public health campaign “wages war” on cancer, or a microbiologist describes a virus as “attacking” a cell, these forceful words create a war-like metaphor for understanding the way disease works. notable work in this area has been done by judy segal, who chronicled the impact of five biomedical metaphors in her book health and the rhetoric of medicine, including ‘‘medicine is war,’’ ‘‘the body is a machine,’’ ‘‘diagnosis is health,’’ ‘‘medicine is a business,’’ and ‘‘the person is genes, ’’ all of which have had academic, cultural, and social impacts on the way medicine is practiced and understood. monika cwiarka has also questioned the use of laboratory mice in behavior-based studies, asking whether certain behaviors observed in mice can be considered analogous to those observed in humans. another important recent study is gronnvoll and landau's research to determine how the public uses metaphor to understand genetic science. hyperbole hyperbole is a figure of speech more often used by a patient when speaking with a doctor than by doctors communicating with their patients. where some figures of speech can help to lend meaning or understanding to medical and scientific communication, hyperbole often obscures the truth by exaggerating it, which can have detrimental and even deadly results. headaches, for example, can occasionally be described by patients as feeling as if their “head’s going to explode.” this type of communication can make it difficult for doctors to understand the true gravity of a symptom, which may lead to misdiagnosis. furthermore, doctors and scientists need to be especially aware of the negative implications that hyperbole can have in medical discourses. as joseph loscalzo points out in his article clinical trials in cardiovascular medicine in an era of marginal benefit, bias, and hyperbole, the use of hyperbole by investigators during medical trials can “often prejudice the trialist in favor of a positive result.” when investigators provide trialists with bias, whether intentionally or unintentionally, the data that is collected may be skewed in the direction of the bias provided by the investigator. stasis consider a hypothetical conversation between two parties about health care reform. one party may wish to argue the moral necessity of health care reform while the other party wishes to argue that health care reform is economically infeasible. until both parties agree on the issue at hand (whether it be the economic or moral considerations of health care reform), resolution of the argument cannot take place. once the parties have agreed on the issue at hand, they have achieved rhetorical stasis. the idea of first agreeing to the issue at hand is central to any discussion between rational people. one example of how stasis can apply to health and medical rhetoric is provided in a recent article by christa teston and scott graham. these researchers applied the rhetorical concept of stasis to medical discourse by reviewing the fda discussion on avastin as a treatment for metastatic breast cancer. they concluded that the absence of stasis resulted in miscommunication between the interested parties. the fda could have achieved stasis, these authors conclude, by first reaching consensus on the following questions: what counts as clinical benefit? what kinds of evidence would be deemed meaningful? rhetorical appeals the rhetorical appeals, often referred to as modes of persuasion or ethical strategies, are a set of rhetorical concepts used to persuade audiences. initially introduced by aristotle in on rhetoric, the appeals focus on three ways to persuade your audience: by appealing to the character of the speaker (ethos), the emotions of the audience (pathos), or the logic/truth of the argument itself (logos). ethos ethos is an appeal to the authority or credibility of the presenter and is especially important in health and medicine communication. as sarah bigi explains in her article the persuasive role of ethos in doctor-patient interactions, “physicians are expected to inform, advise and persuade patients regarding their health problems.” in order to successfully persuade their patients, doctors need to rely on the rhetorical appeals, and the appeal that patients seem to care about the most is the ethos of the doctor. if a doctor does not seem credible, then a patient is unlikely to follow their instructions or diagnosis, which can lead to further health complications down the line. pathos pathos is an appeal to the audience's emotions. the speaker may use pathos in a multitude of ways; however, in terms of the rhetoric of health and medicine, two particular emotions stand out: fear and hope. when doctors appeal to fear it is not done so lightly. doctors have to decide if instilling fear in their patient is the right tactic for persuading their patients to agree with the physician's treatment plan. for instance, if a patient has diabetes and is likely to lose a toe or foot if they do not change the way they treat their condition, it is up to the doctor to decide when to stop telling their patient that “changing your habits will give you a better life” and to start telling their patient that “if you don’t stop your current habits, you’re going to lose a foot.” when doctors appeal to hope, the doctor tries to persuade the patient through describing a scenario of a positive future that's only possible by the patient following the doctor's orders. in some cases, cognitive behavioral therapy, the act of presenting this positive emotional state can actually create a positive result in itself. logos logos is logical appeal or the simulation of it. it is normally used to describe facts and figures that support the speaker's claims or thesis. it is important to health and medicine communications because patients want to know which treatments work best, and they want the scientific data to prove it. having an appeal to logic also enhances ethos because information makes the speaker look knowledgeable and prepared to his or her audience. however, the data can be confusing and thus confuse the audience. so, the doctor has to make sure to leverage the appeals to best persuade their patients. doctors must decide how many facts and figures are appropriate to persuade an audience of the factual basis of the argument while portraying themselves as a credible speaker and playing to the right emotional state of their patient---all to get the patient to follow the doctor's orders. research methodology rhetoricians of health and medicine conduct research primarily through qualitative methods, although quantitative methods are also occasionally employed. scholars in the field apply these techniques to understand how and for what reasons health and medical communication is accomplished. content analysis through content analysis, scholars strive to answer the questions first formulated by political scientist harold lasswell as they apply to health and medicine texts: “who says what, to whom, why, to what extent and with what effect?" for example, researchers might study the content of pharmaceutical advertisements on television to determine their appeals to potential consumers. others might examine the communication of health information via new media such as twitter and facebook. rhetoricians have increasingly turned to computers to facilitate quantitative content analysis as they gather massive data collections from internet sources. survey research researchers in the field are also concerned with the effectiveness of health and medical communications. audience surveys are often used to determine if a target audience understands a given set of health or medical instructions. the results help researchers adjust these instructions and assist audiences in achieving functional health literacy. other surveys gauge the public's attitudes and knowledge regarding important medical topics such as mental health. this sort of research identifies gaps for public health agencies to address in their communications. usability testing creators of health and medical communications often test their work with a subset of their target audience before its wider release. this practice is particularly important when content creators are not themselves part of their target audience, as is often the case for communications that address vulnerable communities such as senior citizens or immigrants with english as a second language. usability research can include techniques such as “think aloud” testing, in which potential users talk the researcher through their navigation of a given computer program or text. evaluations by experts in other fields, such as design or user experience, are also employed.