Diffusion of innovations is the theory of how new ideas spread: why some catch on quickly, some slowly and some not at all, and who adopts them first. It was set out by the sociologist Everett Rogers in 1962, and it remains one of the most widely cited ideas in marketing, public health and technology. Its central finding is simple and still underused: a better idea does not spread because it is better. It spreads through people, in a predictable order, at a speed that depends on the idea's own characteristics.
This article covers where the theory came from, the five groups of adopters, the five traits that decide speed, and what the theory means for anyone trying to spread something new.
What is the diffusion of innovations?
Diffusion is the process by which an innovation, meaning anything perceived as new, from a farming technique to an app, is communicated through certain channels over time among the members of a social system. That is close to Rogers's own definition, and each part matters.
The innovation only has to be new to the people adopting it. The channels include both mass media and person-to-person contact. Time is essential, because adoption is a process, not an event. And the social system, the community, profession or market, shapes how quickly things move through it.
The theory's best-known output is the adoption curve: if you plot how many people have adopted something over time, you usually get an S-shape. Slow at first, then fast, then slow again as the last holdouts come round.
A better idea does not spread because it is better. It spreads because someone people trust uses it first.
Where the theory came from: Iowa and hybrid corn
The theory grew from rural sociology. In 1943 Bryce Ryan and Neal Gross published a study of how farmers in two Iowa communities adopted hybrid seed corn, which produced substantially higher yields than traditional seed.
Despite the clear advantage, adoption took more than a decade. A few farmers tried it early, most waited, and the curve only rose steeply once a critical number of neighbours were using it. The farmers usually first heard about hybrid corn from salesmen, but what actually persuaded them was seeing neighbours use it successfully.
Everett Rogers, who grew up on an Iowa farm, gathered hundreds of diffusion studies from many fields and synthesised them in his 1962 book Diffusion of Innovations. It went through five editions, the last in 2003, and became one of the most cited books in the social sciences.
Check yourselfBefore you read on: a new technology product wins over its first enthusiastic users, and then sales stall. What might the next, much larger group of buyers want that the first group did not?Show the answerHide the answer
Proof. Geoffrey Moore argued in Crossing the Chasm that there is a gap between early adopters, who want something new, and the early majority, who want something proven. A product can excite the first group and still never cross to the second, which is where most of the market sits.
The five adopter groups
Rogers divided adopters into five categories based on when they adopt. The percentages come from dividing a normal distribution at standard deviations, so they are an idealised model rather than a measurement of any particular market.
| Group | Share | What characterises them |
|---|---|---|
| Innovators | 2.5% | Venturesome, comfortable with risk, often connected outside their local community |
| Early adopters | 13.5% | Respected locally, often opinion leaders whom others watch |
| Early majority | 34% | Deliberate, adopt just before the average person |
| Late majority | 34% | Sceptical, often adopt from necessity or peer pressure |
| Laggards | 16% | Traditional, last to adopt, often wary of change itself |
The most important group is not the innovators but the early adopters. Innovators are often seen as unusual, so their adoption does not persuade others much. Early adopters are respected members of the community, and when they adopt, the early majority starts paying attention.
In 1991 the consultant Geoffrey Moore argued in Crossing the Chasm that, for technology products, there is a gap between early adopters and the early majority, because the two groups want different things. Early adopters want something new; the early majority wants something proven. Many products that excite early adopters never cross that gap.
The five traits that decide how fast an idea spreads
Rogers identified five characteristics of an innovation, as perceived by potential adopters, that explain much of the difference in how fast things spread.
Relative advantage. How much better it seems than what it replaces. Not how much better it is, but how much better it seems.
Compatibility. How well it fits existing values, habits and needs. Ideas that require people to change who they are spread slowly.
Complexity. How hard it is to understand and use. Simpler ideas spread faster.
Trialability. Whether it can be tried on a small scale first. A free trial, a sample, a single field of hybrid corn.
Observability. Whether others can see the results. Visible innovations spread faster, because seeing others succeed is what persuades.
How this is taught inside Astra Trainer
The Trends & culture direction in the Marketing, Sales & Attention world covers spotting trends early, explaining why they spread, and reading where they sit in their lifecycle, with courses such as Why Humans Follow Trends, Why New Ideas Spread and The Diffusion of Innovations.
Diffusion theory is the backbone of that material, because it explains why the same curve shows up in farming, fashion and software. Lessons take about five minutes and a guide walks you through anything strange.
Awareness from media, persuasion from people
One of the most consistent findings in diffusion research is that different channels do different jobs. Mass media and advertising are good at making people aware that something exists. Personal contact, especially with people similar to yourself, is what persuades people to actually adopt it.
That was true of the Iowa farmers and it remains true now. It is the same mechanism described in social proof marketing: people look to others like them when deciding what to do. An idea spreads when it moves from advertising into conversation.
It also explains why the article on why ideas spread emphasises visibility: an idea that people can see others using carries its own persuasion with it.
What diffusion theory means in practice
Find the early adopters, not the innovators. Innovators will try anything; their enthusiasm proves little. Early adopters are the respected people others watch. Winning them is what starts the curve rising.
Lower the cost of trying. Trialability is one of the easiest traits to improve. A free first lesson, a sample, a pilot all let people test without committing.
Make results visible. If people cannot see an innovation working, they cannot be persuaded by it. Case studies, public use and word of mouth turn private results into social proof.
Reduce complexity and increase compatibility. Frame the new thing in terms of what people already value and do. The less it asks people to change, the faster it spreads.
Expect the curve to be slow at first. The flat start of the S-curve is normal, not a sign of failure. Many good ideas are abandoned during it.
Run it against something you are trying to spread
Ticked: 0 of 5
Each item maps to one lever in the theory. An unticked item is not a verdict on the idea, only the place where spread is most likely to stall.
Limits of the theory
Diffusion theory has critics. It has been accused of a pro-innovation bias, assuming that new ideas are good and that non-adopters are simply slow, when some innovations deserve to be rejected. The labels, especially "laggards", can read as judgements rather than descriptions. And the neat percentages come from a statistical model, not from measuring any real market.
Rogers himself acknowledged several of these criticisms in later editions. Used as a way of thinking about how ideas move through people, rather than as a precise forecasting tool, the theory remains useful.
Why reading diffusion is a habit
Once you know the curve, you start seeing it everywhere: in the products friends adopt, the phrases that spread through a workplace, the ideas that stall. That kind of noticing gets sharper with practice.
Astra Trainer is built around that kind of practice. Quizzes follow each topic and each course ends with a ten-question final exam, while daily quests, points and a streak keep five-minute lessons going. A Circle gives you a small group with a shared weekly goal and live sessions, useful for comparing what people are noticing before it becomes obvious.
What to take from this
Diffusion of innovations is Everett Rogers's 1962 theory of how new ideas spread through a social system over time, usually in an S-shaped curve.
It grew from studies like Ryan and Gross's 1943 work on Iowa farmers and hybrid corn, which spread slowly despite being clearly better.
Adopters fall into five groups, and early adopters, the respected people others watch, are the key to spread. Five traits of the idea decide its speed: relative advantage, compatibility, complexity, trialability and observability.
Which is why the most useful lesson from the diffusion of innovations is that ideas do not spread on their merits alone. They spread through trusted people, one visible success at a time.
Test yourself
Question 1 of 3
A seed company invites farmers to walk past a neighbour's field of its new corn at harvest time. Which of Rogers's traits is it mainly working on?
What is the diffusion of innovations theory?
A theory developed by the sociologist Everett Rogers in 1962 describing how new ideas, products and practices spread through a society over time. It explains adoption as a social process, usually following an S-shaped curve, driven by communication between people.
What are the five adopter categories?
Innovators, about 2.5 percent; early adopters, 13.5 percent; early majority, 34 percent; late majority, 34 percent; and laggards, 16 percent. The percentages come from a statistical model rather than from measuring a real market.
What are the five characteristics that affect adoption?
Relative advantage, how much better the innovation seems; compatibility with existing values and habits; complexity; trialability, whether it can be tested on a small scale; and observability, whether others can see the results.
What study was diffusion of innovations based on?
One of its foundations was Bryce Ryan and Neal Gross's 1943 study of Iowa farmers adopting hybrid seed corn, which took more than a decade to spread even though it clearly increased yields.
Where can I learn about trends and how ideas spread?
The Trends & culture direction inside the Marketing, Sales & Attention world of Astra Trainer covers why humans follow trends, how new ideas spread and the diffusion of innovations, in five-minute lessons with quizzes. The first lesson needs no card.
Where this leads. How to Grow an Audience From Zero, in Order applies the same logic to building a following, starting with the early adopters.
