This document summarizes Everett Rogers' theory of the diffusion of innovations. It discusses the key elements of the theory, including the innovation itself, communication channels, time as it relates to the innovation-decision process and adopter categories, the rate of adoption within a social system, and the roles of social structure, norms, and opinion leaders in influencing diffusion. The main points are that diffusion is the process by which innovations spread via communication over time among members of a social system, and that this process involves uncertainty reduction as individuals learn about the innovation.

1. What is the diffusion of
innovations?

2. Different Approaches to the
study of innovation.
• Rogers - communications and/as
development paradigm.
• Winston/Bjiker - Science Technology and
Society/SCOT
• Freeman/Soete/Schumpeter - The Economic
importance of innovation.

3. What is diffusion?
• The process by which an
innovation is communicated
through certain channels over time
among the members of a social
system.

4. What is diffusion?
• In this context communication is:
• a process whereby participants
share information to reach a mutual
understanding.

5. What is diffusion?
• Diffusion is a special type of
communication in which the messages are
about a new idea.
• The newness of the idea gives diffusion its
special character – it ensures that a degree
of uncertainty is involved in diffusion.

6. What is diffusion?
• Uncertainty – the degree to which a
range of alternatives are perceived with
regard to the occurrence of an event.
Uncertainty implies lack of
predictability and therefore of
information.

7. What is diffusion?
• Thus information becomes a means of
reducing uncertainty.
• Any technological innovation embodies
information and thus reduces uncertainty
about cause-effect relationships in problem
solving.

8. What is diffusion?
• To put this in a nutshell - for Rogers,
"diffusion of innovations" means
• The dissemination of uncertainty-reducing
information embodied in products or
processes through a social system.

9. The Process of the diffusion of
Innovations
• Diffusion is a process where an
innovation is communicated
through certain channels over time
among members of a social system

10. Four Elements in Diffusion of
Innovations:
• Diffusion is a process where:
• 1) an innovation
• 2) is communicated through certain
channels
• 3) over time
• 4) among members of a social system

11. The Innovation
• An idea, practice or object that is perceived
as new by an individual or other unit of
adoption.

12. The Innovation
• “An invention is an idea, a sketch or model for
a new or improved device, product, process or
system. Such inventions may often be patented
but they do not necessarily lead to technical
innovations. In fact the majority do not. An
innovation in the economic sense is
accomplished only with the first commercial
transaction involving the new product, process
system or device.” Freeman & Soete, p. 6.

13. The Innovation
• TECHNOLOGICAL INNOVATIONS,
INFORMATION AND
UNCERTAINTY.
• Technology: “ a design for instrumental
action that reduces the uncertainty in the
cause-effect relationships involved in
achieving a desired outcome.”

14. The Innovation
• Technological has 2 components:
• Hardware (physical element)
• Software – the information base for the tool.
• A technology may be almost entirely composed of
information.
• This will tend to slow its diffusion because of poor
observability

15. The Innovation
• Technology is a means of uncertainty
reduction that is made possible by
information about the cause-effect
relationships on which the technology is
based.

16. The Innovation
• Technological innovation both creates one
kind of uncertainty and represents an
opportunity for reduced uncertainty in
another sense:
• Increased uncertainty (about the innovation’s
expected consequences)
• Reduced uncertainty (deriving from the
information base of the technology)

17. The Innovation
• Uncertainty reducing potential provides the motivation for
the individual to learn about the innovation
• One information-seeking has reduced uncertainty about the
innovations expected consequences to a tolerable level, a
decision concerning adoption will be made
• Thus the innovation-decision process is essentially about
information seeking, allowing the individual to reduce
uncertainty about the advantages and disadvantages of the
innovation.

18. The Innovation
• Two kinds of information with regard to a
technological innovation:
• Software information –– what does it do? How
does it work?
• Innovation-evaluation information –What are an
innovation’s consequences? What will its
advantages and disadvantage be in my situation?

19. The Innovation
• Technology Clusters –several
distinguishable elements of technology
perceived as being closely interrelated.
• Relevance - Experience with one part of a
technology cluster conditions assessment of
new technologies in the same cluster

20. The Innovation
•
•
•
•
•
•
Characteristics of Innovation –
Relative Advantage
Compatability
Complexity
Trialability
Observability

21. The Innovation
• Relative Advantage – over existing
technologies - can be perceived,
may be measured in economic
terms, social prestige, convenience
and satisfaction.

22. The Innovation
• Compatibility – with existing values, past
experiences, needs of potential adopters
(and their social system)
• Complexity - degree to which an innovation
is perceived as difficult to understand and
use.

23. The Innovation
• Trialability – degree to which an innovation
may be experimented with on a limited
basis. A trialable innovation represented
less uncertainty to a potential adopter.
• Observability – Degree to which the results
of an innovation are visible to others.

24. The Innovation
• Re-invention – adopting an
innovation is not necessarily the
passive role of just
implementing a standard
template of a new idea.

25. .
Communications Channels
• The means by which messages get from one
individual to another.
• The nature of the information-exchange
relation determines the conditions under
which a source will/will not transmit the
innovation to the receiver and the effect of
the transfer.

26. Communications Channels
• Mass-media – most efficient way to create
awareness knowledge of an innovation
• Interpersonal channels – more effective in
persuading in individual to accept a new
idea.

27. Communications Channels
• Individuals do not evaluate innovations on
the basis of a scientific assessment of its
consequences – rather depend on subjective
assessment conveyed to them from peers.
Thus diffusion is a social process.

28. Communications Channels
• The closer (more homophilious) two
individuals are, the more frequently and
more successful the transfer of ideas
between them.

29. Communications Channels
• Problem - in the diffusion of innovation: is
participants are usually quite heterophilious
– thus ineffective communication likely to
occur.
• Yet two exactly similar individuals cannot,
by definition pass on information. Therefore
diffusion demands some heterophiliousness.”

30. Communications Channels
• Time - third element in the diffusion
process. Involved in:
– the innovation-decision process
– the innovativeness of an individual
– an innovation’s rate of adoption in a system

31. THE INNOVATION-DECISION
PROCESS.
• THE INNOVATION-DECISION
PROCESS - the process through which an
individual passes from first knowledge of
an innovation to forming an attitude toward
the innovation, to a decision to adopt or
reject it.

32. THE INNOVATION-DECISION
PROCESS.
• Five stages in the innovation-decision
process:
•
•
•
•
•
(1) knowledge,
(2) persuasion,
(3) decision,
(4) implementation, and
(5) confirmation.

33. THE INNOVATION-DECISION
PROCESS.
• Knowledge occurs when an individual (or other decisionmaking unit) learns of the innovation’s existence and gains
some understanding of how it functions.
• Persuasion occurs when an individual (or other decisionmaking unit) forms a favourable or unfavourable attitude
toward the innovation.
• Decision occurs when an individual (or other decisionmaking unit) engages in activities that lead to a choice to
adopt or reject the innovation.

34. THE INNOVATION-DECISION
PROCESS.
• Implementation occurs when an individual (or other
decision-making unit) puts an innovation into use. Reinvention is especially likely to occur at the
implementation stage.
• Confirmation occurs when an individual (or other
decision-making unit) seeks reinforcement of an
innovation-decision that has already been made, but the
individual may reverse this previous decision if exposed to
conflicting innovation.

35. THE INNOVATION-DECISION
PROCESS.
• At the knowledge stage the individual
wants to know what the innovation is and
how and why it works.
• Mass media channels

36. THE INNOVATION-DECISION
PROCESS.
• At the persuasion stage the individual wants
to know the innovation’s advantages and
disadvantages in his or her own situation.
• Interpersonal networks

37. THE INNOVATION-DECISION
PROCESS.
• Ultimately, the innovation-decision process
leads to either adoption or to rejection.

38. INNOVATIVENESS AND ADOPTER
CATEGORIES.
• “Innovativeness” - the degree to which an
individual or other unit of adoption is
relatively earlier in adopting new ideas than
the other members of a system.
• Members of each of the adopter categories
tend to have a good deal in common.

39. INNOVATIVENESS AND ADOPTER
CATEGORIES.
• The adopter categories
•
•
•
•
•
(1) innovators,
(2) early adopters,
(3) early majority,
(4) late majority, and
(5) laggards.

40. INNOVATIVENESS AND ADOPTER
CATEGORIES.
• Late majority category - characterised by:
– low social status,
– making little use of mass media channels
– learn about most new ideas from peers via
interpersonal channels.

41. INNOVATIVENESS AND ADOPTER
CATEGORIES.
• Innovators:
– active information-seekers about new ideas.
– have a high degree of mass media exposure
– their interpersonal networks extend over a wide
area.
– can cope with higher levels of uncertainty about
an innovation than are other adopter categories.

42. RATE OF ADOPTION
• Rate of adoption - the relative speed with
which an innovation is adopted by members
of a social system.
• When the number of individuals adopting a
new idea is plotted on a cumulative
frequency basis over time, the resulting
distribution is an “S-shaped curve.”

43. RATE OF ADOPTION
Figure 3.1: Telephone Development 1922 - 1997, Basic Indicators
1600000
1400000
1200000
1000000
800000
600000
400000
200000
0
Number of
Telephones

44. Rate of Adoption
• Most innovations have an S-shaped rate of adoption.
• But there is variation in the slope of the “S” from
innovation to innovation;
• some new ideas diffuse relatively rapidly and the S-curve
is quite steep.
• Other innovations have a slower rate of adoption, and the
S-curve is more gradual, with a slope that is relatively
lazy.

45. Rate of Adoption
• There are also differences in the rate of
adoption for the same innovation in
different social systems.

46. A Social System
• Defined as: a set of interrelated units that
are engaged in joint problem-solving to
accomplish a common goal.
• This sharing of a common objective binds
the system together.

47. A Social System
• The social structure of the system affects
the innovation’s diffusion in several ways.
Here we deal with:
– how the system’s social structure affects
diffusion,
– the effect of norms on diffusion,
– the roles of opinion leaders

48. Social Structure
• To the extent that the units in a social
system are not all identical in their
behaviour, structure exists in the system.
• Structure - the patterned arrangements of
the units in a system.

49. Social Structure
• Structure gives regularity and stability to
human behaviour in a system; it allows one
to predict behaviour with some degree of
accuracy.
• Structure represents one type of
information, in that it decreases uncertainty.

50. Social Structure
• An illustration of this predictability - is structure in a
bureaucratic organisation. Here there is a well-developed
social structure, consisting of hierarchical positions, giving
officials in higher-ranked positions the right to issue orders
to individuals of lower rank. They expect their orders to
be carried out.
• Such patterned social relationships among the members of
a system constitute social structure, one type of structure.

51. Social Structure
• We can also have a communication structure,
defined as:
• the differentiated elements that can be recognized
in the patterned communication flows in a system.
• Communications structures are interpersonal
networks linking a system’s members,
determining who interacts with whom and under
what circumstances.

52. Social Structure
• A complete lack of communication
structure in a system would be represented
by a situation in which each individual
talked with equal probability to each other
member of the system.
• Class in society can be regarded as both a
social structure but also a communications
structure.

53. Social Structure
• Regularized patterns of communication within a
system predict, in part, the behaviour of individual
members of the social system, including when
they adopt an innovation.
• Thus it is difficult to study how innovations
spread without some knowledge of the social
structures in which potential adopters are located.

54. SYSTEM NORMS AND
DIFFUSION.
• Norms are: the established behaviour patterns for the
members of a social system. They define a range of
tolerable behaviour and serve as a guide or a standard for
the members’ behaviour in a social system.
• The norms of a system tell an individual what behaviour is
expected. Thus a system’s norms can be a barrier to
change.
•
Norms can operate at the level of a nation, a religious
community, an organisation, or a local system like a
village.

55. OPINION LEADERS
• Most innovative member of a system often
perceived as a deviant from the social
system
• Thus is accorded low credibility by the
average members of the system.
• Thus their role in diffusion is likely to be
limited.

56. OPINION LEADERS
• Other members of the system function as
opinion leaders. They provide information
and advice about innovations to many in the
system.
• They are opinion leaders

57. OPINION LEADERS
• Opinion leadership is: the degree to which an individual is
able to influence other individuals’ attitudes/behaviour.
• This leadership is not a function of the individual’s formal
position.
• Opinion leadership is earned and maintained by the
individual’s
– technical competence,
– social accessibility, and
– conformity to the system’s norms.

58. OPINION LEADERS
• Thus when the social system is oriented to
change, the opinion leaders are quite
innovative; but when the system’s norms
are opposed to change, the behaviour of the
leaders also reflects this norm

59. OPINION LEADERS
• . When compared with their followers
opinion leaders are:
– are more exposed to all forms of external
communication,
– have somewhat higher social status, and
– are more innovative (although the exact degree
of innovativeness depends, in part, on the
system’s norms).

60. OPINION LEADERS
• Opinion leaders occupy an influential
position in their system’s communication
structure:
• They are at the centre of interpersonal
communication networks - interconnected
individuals linked by patterned flows of
information.