Rogers work has been so widely cited for at least two reasons:
- The concepts of innovation, adoption, and diffusion are wide-ranging. Sure, his work was on farmers in Iowa, but my examples of his concepts went all over the place--communications, transportation, domestic lighting, you name it. Basically, these are universal concepts, and they play out on both macro and micro levels. (If you want to read Rogers' book, it's stuffed with fascinating vignettes. Why do we have QWERTY keyboards instead of Dvorak? Why are the tomatoes you buy in the grocery store hard while the ones your grow in your garden are soft?)
- It's held up shockingly well in field after field. Basically, Rogers ideas have been applied again and again in many different contexts (medicine, public health, business -- again, you name it!) and his theories have proven to be useful descriptors and even predictors (which is the ultimate test of a theory).
Happily, his major insights can be conveyed pretty rapidly.
First, every innovation has five key characteristics
- Compatibility: How well does this innovation fit with existing values, patterns of behavior, or tools? The adoption of vaccination, for example, needed (and still needs??) to overcome certain patterns of belief.
- Trialability: Can you try it before you buy it? Can you test drive the car or do you have to buy it before discovering that it looks like a fish but steers like a cow? Basically, when a software vendor gives you a 45-day free trial (or whatever), they're trying to make their product trialable. When a food company does a grocery store promotion (giving away free samples), they making their product trialable. Even a coupon is an an example of this -- the company is lowering the price of trying out their product.
- Relative advantage: In what way is this innovation better than the alternatives? If this seed doubles my yield per acre but causes me to spend ten times as much on pesticides and fertilizers, then maybe it doesn't have such a great relative advantage.
- Observability: This is a form of advertising: If someone else is using the innovation, can I see it being used? Are its benefits noticeable? If you can recall when Apple was rolling out the iPod, the marketing involved images of white earbuds. It was a little odd, at the time--earbuds were typically utilitarian black, nondescript; these white things seemed startlingly out of place. However, I eventually recognized that this tactic was a way of boosting observability: I could see someone with the (then) distinct white earbuds and know, "Hey, they've got one of these new iPod thingies!" instead of some other media player (random mp3 thingie, CD player, or -- God forbid -- cassette player).
- Simplicity / Complexity: The easier it is to learn or grasp, the faster it diffuses. Global climate change is, unfortunately, a very complex idea. It's going to take a while for people to fully grasp it. (Sad experiment: Asking grad students at MIT to explain the dynamics behind it and finding that even they are bad at understanding it, or at least bad at explaining their understanding. See Sterman & Sweeney, 2004.) Conversely, the complexity of many pro-energy policies is much lower (e.g., the Keystone Pipeline = jobs! Lowers energy costs!) and therefore they tend to diffuse more successfully (even if they're not completely true).
An innovation that is compatible, trialable, offers relative advantage, observable, and isn't too complex is more likely to be successful than one that is not or only has a few of these characteristics. These characteristics aren't defining -- policymakers can still enforce adoption or non-adoption -- but they are influential. The Volkswagen and the Lada both emerged from totalitarian states, but one offered a heck of a lot more relative advantage than the other. One is now a beloved premium brand, and the other is a punchline to a joke that fewer and fewer people have ever heard of.
Rogers' second main idea is the modeling of adoption throughout a population. Let's borrow an image from the wonderful folks at Wikimedia:
The blue curve shows the way a population comes to adopt a hypothetical successful innovation: at first just a few, then a few more, then the majority, and then a tail end. For example: I still don't have a smartphone, a fact which increasingly infuriates my wife. Am I a laggard? Just late majority? (I guess it depends on how annoying I am being on any given day.)
The yellow curve shows the total percentage of adopters over time -- in other words, keep adding each new increment of adopters on top of the old ones. When the first few people adopt something, the adoption rate goes from zero to something in the single digits. It climbs steadily until the last few adopters, therefore, finally push it up to close to 100%. (But maybe I'll still be there, clutching my dumb phone, so perhaps it never gets to 100%. I am fully vaccinated, however!)
Note that these concepts only apply to successful innovations. Failed innovations never break out from innovators or early adopters or never pass a certain threshold of early majority. Or perhaps a new innovation comes along that completely swamps them. (Anyone still own an 8-track cassette player? Betamax?)
Also, these are generalized, hypothetical constructs. Each innovation has its own curve. A rapidly-adopted innovation (cellphones, for example, tend to be quickly successful wherever they are introduced, although this is for a variety of reasons) will have a more bunched-together bell curve (the blue line) and consequently a steeper S-curve (the yellow line). A slower-diffusing innovation (electric cars?) will have a broader/flatter bell curve and a more stretched-out S curve.