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Introduction: How 'Channel' fits into the Input/Output and the "4 P’s" Models

To review McGuire’s inputs: the “source” is the who, the “message” the what, the 'channel' the how, the “audience” the to whom, and the “destination” the why or overall purpose of the message or campaign. The channel is our mechanism for sending the message, or in other words, the medium through which the message is sent. Traditionally, 'channel' derives from 20th century radio and television, referring to a specific TV, AM, or FM broadcast station. Famed "The Medium is the Message" saw the channel (or 'medium') as the central aspect of communication. Manifested in his oft-cited quote "the medium is the message," McLuhan held that the medium leads the way in attracting an individual's awareness and will shape how a message is understood (today, we could give the example of how identical messages may be perceived differently if seen on TikTok versus heard from a friend's mother). From a more current social marketing perspective, the channel largely corresponds to the “place” where we find the audience, whether they are watching TV in their home, browsing the Internet or looking at their cellphone screen, or even sitting in a medical clinic waiting room.

​The utility of a specific channel or, for that matter, the decision whether to launch a campaign in the first place, may depend to a great extent on the target behavior or other desired action that we promote—in other words, whether our mission is to announce, advise, activate, or advocate (see the Messages module’s Campaign Objectives). For instance, a meta-analysis conducted by Snyder et al. (2004) looked at 3 types of campaigns: those that promoted healthy behavior adoption, unhealthy behavior prevention, and reduction/cessation of unhealthy behavior. Their results indicated that campaigns focusing broadly on, for example, oral health and seat belt use, were slightly more successful than campaigns focusing on other topics, possibly because their destination involved relatively easier behavior changes. Conversely, mass media messages emphasizing the full cessation of an addictive behavior (especially smoking cessation) may have less of an impact on the audience than those directed at non-addictive behaviors, including preventing the spread of COVID-19 and other infectious diseases. Campaigns promoting more difficult behavior change may require multiple channels and messages, certainly to include frequent and ongoing interpersonal advice and support. Therefore, audience research is needed to determine whether mass media platforms comprise appropriate channels for communication, or whether face-to-face or clinic-based interventions with peers or health professionals as the source may be the most effective avenue toward achieving a public health change.

Part One: Types of Channels and Media Delivery Systems


In health communication and marketing circles, channels typically refer to types of communication prevalent during the second half of the 20th century up to the present day. The previously dominant channels comprised the broader categories of broadcast (television and radio), circulating print (newspapers and magazines), display print (billboards, posters, and other signage), and face-to-face communication. Today, when thinking of channels, we often begin with social media platforms and other web-based media. However, as with interpersonal communication (see below), social media can be looked at as either “media” (another word for “channels”) or “media delivery systems.” Media delivery systems comprise an aggregated super channel that consists of two or more specific channels. In other words, social media (i.e., digital distribution) and face-to-face communication involve not only single, specific channels; they can be used simultaneously to deliver print, graphic, and even video presentations. Therefore, the specific individual or social medium at the same time represents a multifaceted system through which individuals access a variety of communication messages via the diverse individual channels. ​

​Currently, the concept of channels includes social media, advertising, public relations, display print (e.g., posters, billboards, grocery store shelf markers), special promotional items, signage, personal selling, and streaming and other popular media through which “entertainment-education” is typically delivered. Again, as messages are the what of communication and the source is the who of communication, channels are the how of communication.

Advertising, whether it’s paid or gratis, is typically carried out through mass media such as web-placed ads, broadcast or streaming, circulating print, direct mail, innovative uses of print media that have other purposes (e.g., using the backs of tickets, receipts, or bills), or outdoor displays such as billboards. In the 20th century, broadcast media comprised television and radio. Both of these media, especially AM/FM radio, have diminished in popularity given the vast array of broadcast channels available—in the United States, the 3 national television broadcast networks (ABC, CBS, and NBC) no longer dominate the airwaves, and even cable is being eclipsed by streaming services. Audiences have access to 24-hour news programs, on-demand video streaming, XM radio, and hundreds of other cable and broadcast channels, and radio in general is no longer a preferred medium for advertising and health communication. Nevertheless, radio is still an appropriate and effective outlet for various public service announcements (PSAs) and for reaching audiences in less heavily populated rural regions in areas within the United States and Canada, or in developing countries like Kenya (note the unique target audience of the latter: passengers in mini-busses).

Regardless of recent trends in audience behavior, radio has a long and storied history in mass education, whereby groups of students, usually guided by a teacher and/or structured textbooks, tune in regularly to receive instruction broadcast on a specific station, such as is possible with the many pieces developed by EDCWorldwide.

The category of mass media also includes robocalls, text messages, and Internet-delivered messages either through active (when the audience proactively accesses and interacts with the message) or passive presentation (e.g., through the use of pop-up ads in YouTube videos). Advertisements in movie theaters or in streamed programs, either before the beginning of a feature or placed in the feature itself, is a form of broadcast communication. Nevertheless, such placement most often has been used in contradiction to public health goals (e.g., in the depiction of drinking, unsafe driving and unprotected sex, and violence; see Analysis Activity 2, below).

Special promotional items are used to imply an endorsement or use of a particular message or other product. Clothing such as T-shirts, hats, lapel pins, balloons, and functional items (e.g., keychains, water bottles, pens, grocery bags) can all be used to promote a specific product or message, some of which have only indirect references to health actions, whereas others are specifically linked.

Signage and displays can include billboards and electronic signs to communicate to drivers and passengers, as well as more detailed and smaller signs placed on or near sidewalks where pedestrians and bicyclists can easily see them. Personal selling through face-to-face meetings, live interactive phone calls, or social media also comprise the use of channels.

Analysis Activity 1 

Examine a few of these billboards. Choose 3 of them that seem to have distinct audiences. Without commenting on the quality of the specific messages, where would you place them for maximum reach? In other words, where would they best find the audience? Provide the links to or the actual images of your selections. 

Any mass medium can also be used to convey unhealthy behaviors. For instance, we can always be suspicious if we see an individual depicted in a contemporary movie smoking a cigarette or having a clearly labeled alcoholic drink when that particular behavior has nothing to do with the plot of the movie or the development of that character. In fact, gratuitous smoking in movies has a very long and sordid history; see this clip from "The Maltese Falcon," where Humphrey Bogart doesn't even have to drop his cigarette to take a pistol away from Peter Lorre. This tradition of presenting smoking that has little or nothing to do with the movie plot has lasted unto this day, in spite of cigarettes having exacted a deadly toll on dozens of Hollywood celebrities (including Bogart).


Research Activity 1

Find a video clip or a still from a movie or television show that seems to gratuitously promote unhealthy behaviors and briefly note why it’s superfluous to the show.

Part Two: Choosing Your Channel


How do we choose the best channel? Typically, this is driven by a pragmatic balance of 3 variables: reach, frequency, and exposure time. "Reach” represents the number of individuals our message can get to through a specific channel, with social and broadcast media offering much larger reach than, for example, face-to-face communication through community health workers. The “frequency,” or number of times an individual is exposed to a message (as well as the diversity of channels through which they are exposed), can also be very important. Frequency by itself may be less important than the cumulative time an individual is exposed to a message; one criticism of social media is that individuals may spend only seconds examining different messages, even if they return to a specific message later. In any case, most campaign budgets are too limited achieve maximum reach, exposure time, and frequency concurrently. The ideal balance must be carefully determined.  (The significance of 'place' as a function of the channel most likely to 'find' an audience changed dramatically at the start of the Covid-19 pandemic in 2020, with more people working remotely and accessing media convenient to being at home. For many, this change has become permanent).

Innovative uses of 'place,' such as advertisement screens in convenience stores, will reach a very specific audience that may be interested in the ad being presented and may not otherwise access it. These consumers represent the perfect "captive audience." A video screen above a gasoline pump will expose the consumer to an ad for at least the length of time it takes for a vehicle's gas tank to be filled. (Note that this medium is sufficiently promising to the point where entire companies feature it as their product).

Circulating print media allows for the sharing of extensive detail to an individual. Although 'readership' is arguably more important than circulation per se (see the "measuring audiences to printed publications" section of the hyperlink), both factors enter into the potential exposure of print information to the public. For example, there are many facets to home care and self-care for diabetes management, arthritis pain management, and other chronic problems. Simply providing this information in a 30-second television ad or a short patient-provider clinical session will too often result in confusion, error, and even complete failure to follow up on the advice. Individuals who have similar information through circulating or self-retaining print can re-access the information at their convenience. The problem with circulating print, however, is that it is usually unidirectional: the writer communicates to the target audience, but the target audience gives us no indication as to whether they understand the writing or find it interesting. Finally, it must be noted that with the advent of social media, popularity of print material has declined to the extent to which newspapers and magazines are going out of business or, at a minimum, have reduced the length and depth of their information and have lost much of their customer base. A great deal of information that would have been presented via circulating print a quarter of a century ago is now more typically accessed online.

Display print represents a good opportunity for finding customers where they are, especially in terms of point-of-purchase. Other forms of display print are standard billboardsdigital billboards, and other formats. Display print typically is used to deliver a brief message; a customer who walks or drives past a display will not be able to study detailed information to any extent. Disadvantages of displays are that production and space rental may be expensive and may be difficult control (such as ensuring that the shelf marker, poster, or other display stays in place).

Radio presentations are fairly infrequently used today but share many of the strengths and weaknesses of television. They can reach large numbers of people over a large region and can reach them at a time and place where they may have time to interact with a message. For example, radio ads during rush hours before and after workdays can capture a listener if that listener happens to be tuned in to the appropriate station. Podcasts such as TED Talks have evolved from this traditional channel, although they may also be accessed via cell phones and other devices. 

Television provides visual stimuli to accompany the information delivered via sound as well as signage, therefore giving it many advantages over radio. Televised or streamed images and video can also show a role model engaging in a complex behavior that cannot be adequately presented in brief format such as signage, or effectively presented via circulating print or radio. If paired with a popular program, televised messages can have a very large reach. But for that reason, they are very expensive. Also, in the United States, public service announcements may be an effective way to get a message on television (such as this promotion of STEM education targeting diverse women), but they’re typically presented during times of low viewership, as the television stations and networks cannot make as much money through selling ads at that time of the day. Like radio and display print, it is also difficult to target PSAs to subgroups of people, and of course they cannot be tailored at all to a specific individual. Thus, most health-related TV ads promote a health service or product to attract customers, such as these two.

Finally, telephone (land line or cell phone) messages through real-time interaction can be a highly effective channel of communication. They have, of course, many of the same features as interpersonal communication and can even include some formats such as FaceTime, Skype, or other video depiction of the sender of the message. Telephone communication, however, has become logistically more challenging as individuals screen calls to avoid speaking to others whom they don’t know or with whom they don’t wish to converse. A negative reaction and public relations damage may accrue to certain types of phone campaigns as well; robocalls have become increasingly unpopular. Following the medical maxim of primum non nocere (“first, do no harm”), channels that risk harming the reputation of a health campaign or its broader purpose should be avoided.

The nearly universal use of cell phones has changed the primary method in which the telephone channel is used. Text messaging all but eliminates the “place” limitations of land lines and even PC-based social media use that require the audience to be in an office, at home, or in another stable location. Mobile phones can also be used to access diverse social media platforms such as Facebook, Instagram, and Twitter, and are used at least daily by the vast majority of teens and adults in the United States—thus, the cell phone has gone beyond being the modern telephone channel, evolving into perhaps our most prolific media delivery system. As such, the cell phone allows for two-way communication between source and audience, giving it an advantage over most radio, TV, and print media. Smoking cessation and medication adherence are two of the scores of behaviors that have been successfully targeted by cell phone intervention. But the cell phone has even gone beyond two-way communication, being used to monitor the owner’s physical activity, diet, and other behaviors. With their Global Positioning System (GPS) capacity, cell phones help commercial and political interests locate consumers and voters, bringing into question our right to privacy. 

Analysis Activity 2 

In one sentence each, categorize the channel being depicted in each of these 4 pieces around the themes of date rape and sexual violence. (Note: some of these pieces could be used on two or more channels).

Analysis Activity 3

Given the apparent purposes of these pieces, are these the most effective channels? Whether or not they seem to be, if you had a very limited budget, what channel(s) would you use? [Note: please critique the channel itself rather than the specific message being depicted]. Choose ONE of the above examples to comment on and suggest changes to.

Analysis Activity 4

Which of the channels highlighted in bold above (in Part Two) does former SNL star comedian Leslie Jones employ to present her pro-choice message? Does she use a media delivery system, and if so, what is it? (Note: This SNL piece seems to have anticipated that reproductive rights would become central to the 2022 elections - as they may in 2024. In any case, it's a great example of effective message heat).

Part Three: The Interpersonal Channel


(Note: see also the closely related upcoming modules on “patient-provider communication” and “public speaking”).

The primary advantage of interpersonal communication is that it not only provides the audience with new knowledge and skills, but at the same time can allow for the source to give emotional and logistical support while providing feedback and reinforcement in subsequent encounters. Thus, interpersonal communication optimizes both frequency and exposure time. An additional important advantage in most cases is that the audience has frequent contact with the communication, especially if he or she shares the same community, work place, or other daily environment. This gives the person in the target audience a chance for frequent interaction with both the message and source. Also, interpersonal communication is the fundamental, traditional core of communication; it is eternal and global, and exists across animal species. Thus, the interpersonal channel is adapted and adaptable to all cultures and communities.


In health communication campaigns, interpersonal communication is often structured and deployed through “community [or ‘lay’] health advisers”. Community health advisers tend to be one or more of the following: 1) fellow participants in a health program; 2) lay volunteers; 3) individuals identified as common sources of health communication, including traditional healers and caregivers; 4) opinion leaders in a community or neighborhood; 5) paraprofessionals and students; and others. Generally, community health advisers are individuals not formally (or at least not extensively) trained to perform primary care or professional health education. Nevertheless, they can have an important informational and emotionally supportive impact, such as through the success of the JCP Salon Breast Cancer Awareness promotion (a great example of how to promote source credibility). Additionally, the extraordinarily successful BRAC program in Bangladesh uses a variety of media, yet fundamentally bases its program on village by village face-to-face communication for health, the empowerment of women, and economic development.

Effective community health advisers generally have the attributes and leadership of, and compassion, and familiarity with a community. Interpersonal communication via community health advisers addresses the weaknesses of an impersonal mass media which tend to be unidirectional and may not result in sufficient frequency, exposure, attention, or comprehension. Community health advisers communicate on a face-to-face, or at least a regular, real-time basis, reducing misunderstanding of treatment or prevention communication while ideally increasing its acceptability and being able to tailor messages to each individual with whom they communicate. Let’s now examine two very distinct uses of community health advisers, one from the United States and the other from Indonesia.

Example 1: Project SHOUT


A good example of the use of lay health advisers was with Project SHOUT (“Students Helping Others Understand Tobacco”). Project SHOUT, shown in the example below, aimed to prevent the uptake of smoking and smokeless tobacco use among students who were initially in the seventh grade (approximately 12 years old).

Previous programs before Project SHOUT had used high school students or even participants from smoking prevention groups in middle schools, but Project SHOUT took into account that such very young students were often not reliable in terms of showing up for training or implementation of the program. Therefore, Project SHOUT community health advisers were university students of approximately 19 or 20 years of age. Thus, the students could still “speak the language” of the seventh graders while being more mature and responsible. Moreover, these university students were seen as highly credible sources of information; the seventh graders could still relate to them in terms of their age (contrasted to school teachers or professors, for example) while holding them in esteem since they came from the same neighborhoods as the seventh graders themselves and found success by going to a university.

The university students then visited seventh grade classrooms in 12 different schools and had the various participants engage in role-playing on how to refuse offers of cigarettes and otherwise avoid the risk of becoming a smoker. The seventh graders received feedback and reinforcement for successful participation in the role plays. Although the initial impact was noticeable, it wasn’t until the seventh graders eventually went into high school (at the age of 14/15) when Project SHOUT switched to a telephone format. Instead of visiting classrooms of 30 students, the university students had one-on-one conversations during “latchkey hours” with each student who continued to participate. Thus, even though it was by telephone and therefore outside of the immediate visual environment, the then ninth grade students felt like they had individual attention, and most reported looking forward to the telephone call interactions. The results of this effort showed that the control group continued to take up the smoking habit while the intervention group (those receiving both the classroom intervention in seventh grade and the telephone calls beginning in ninth grade) continued not to smoke cigarettes. Although it is not certain, this probably can be attributed to the fact that there was an individual, one-on-one connection between the university student and the high school student, and the university student was able to tailor the message directly to the high school student. The long-term impact showed some of the best smoking prevention results in the published research literature.

Example 2: Kader in Indonesia


A very different example of the use of community health advisers comes from Indonesia. The Indonesian Ministry of Health relies greatly on a network of over a million kader (literally, health 'cadres' of community health volunteers) to bring primary health care to the village level. The West Java Department of Health’s Control of Diarrheal Disease (CDD) Program was one of many specialized units around the world to fight what was then the globe’s #1 killer: dehydration due to diarrhea, especially in children under 5. An extensive research and development effort was taken to produce effective job aids for the kader in CDD and a training program to teach their use. A set of counseling cards was produced to provide these minimally educated kader with a tool to diagnose and treat diarrhea and teach the proper use of oral rehydration salts (ORS). These cards were developed as a type of portable supervisor for the kader, as the diagnostic and treatment steps in infant and childhood diarrhea are complex and easily confused. In fact, village health kader often performed only minimal tasks (such as weighing babies and recording their growth), and evidenced a very high dropout rate, possibly due to frustration from not being able to accomplish more.

The cards’ effectiveness was assessed through observations of kader performance and interviews with mothers they had counseled. In the specially trained group, 15 kader underwent 2 days of training to use the cards when diagnosing and advising treatment of cases of diarrhea in their villages. The 16 control group kader received comparable CDD training without the cards. Each group of kader was also given a list of local mothers to test their level of knowledge of CDD and to observe their ability to mix ORS and administer it properly, step by step.  Significant performance differences between the intervention kader and mothers and the control kader and mothers were demonstrated. The intervention kader were consistently more accurate in their diagnoses (using the first card, translated into English) and recommendations for treatment. Mothers counseled by the intervention kader also prepared ORS significantly better than the mothers counseled by the control kader (see the full article). In the 30 years since this effort was undertaken, the counseling card approach has been adapted around the world to address a wide range of health problems.

In conclusion, lay health advisers not only demonstrate efficacy, but often the potential for being broadly effective in the long run. However, they require a lot of a professional's time in terms of training, recruitment, and sustainability. There often is a high dropout rate among lay health advisers, especially if they are volunteers or persons who may be moving on towards higher-paying jobs. Community health adviser programs can be especially effective if backed by policy changes such as giving these advisers college credit for their work. These and other incentives need to be identified to make community health advising truly a public health channel.

It is important to note that community health advisers need to be chosen through careful audience research in terms of what qualities their ideal type of adviser would have. See the Audience module for more information.

Note that in this section we are NOT discussing patient-provider communication, a subject for a later module. But that is germane to our point about the fundamental but often overlooked impact of interpersonal communication. For example, see one of the powerful TED Talks presentations by Dr. Abraham Verghese as he presents the importance of physicians staying in touch with their own humanity as they travel with the patient back to wellness or to the end of life.  

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