Page 182 - JOURNAL OF LIBRARY SCIENCE IN CHINA 2015 Vol. 41

Ge SONG / The diffusion process of academic innovation 181

disciplines. By summarizing the research methods and procedures, this paper attempts to provide a
clear research idea for the future studies on the diffusion of academic innovation.

1 Research methods and indexes

1.1 Diffusion theory

Research on the diffusion of innovation has been independently conducted in several fields, such
as Sociology, Anthropology, Education, Communication, Psychology, Administration, Marketing
and Epidemiology. Despite the distinctiveness of the approaches applied in their diffusion research,
researchers in different fields uncovered almost similar findings that the diffusion of an innovation
followed an S-shaped curve over time.
The reason why the whole process of innovation diffusion exhibits an S-shaped curve is that the
adoption time are normally distributed. Cumulative curve of the bell curve is S-shaped curve. The
formation process of a normal distribution of time adoption can be summarized as the following
steps: first, few actors adopt the innovation; then, the total number of adopters has a sharp rise
along with the role of information and uncertainty reduction in the diffusion of an innovation; and
then the diffusion effect begins to level off after half of the individuals in a social system have
adopted it, because non-knowers become increasingly scarce; finally, the number of new adopters
decreases rapidly and the diffusion process slowly reaches its end. The diffusion curve should be
a typical S-shape, which can be divided into four stages: start stage, take-off stage, maturity stage
and decline stage. However, not all innovation diffusion shows S-shaped curve. S-curve can only
explain the situation to successful innovation diffusion. If it is an unsuccessful diffusion, the rate of
adoption would be plateaued.
Main concepts and indices in diffusion theory can be defined as follows:
1) Adoption rate: the number or percentage of new adopters at a particular moment.
2) Adoption acceleration: the amount of change to adoption rate.
3) Critical mass: the minimum number of adopters needed to sustain a diffusion process.
Once a sufficient number of individuals have adopted, social contagion fuels the process and
causes a chain reaction that ensures wide and rapid diffusion. Then, no more outside input to the
diffusion process is required. Critical point is generally the first second-order inflection point of
the S-curve.
4) Second-order inflection point: the period with the highest adoption acceleration. Hereafter
the acceleration of the adoption rate decreases although the adoption rate still increases in absolute
numbers.
5) First-order inflection point：the period with the highest adoption rate, that is, the largest
absolute increase in new adopters. Usually, the first-order inflection point occurs when
approximately 50 percent of all eventual adopters have adopted.