Exploratory Social Network Analysis

Diffusion

DIFFUSION

• Diffusion is Brokerage with a TIME Dimension

• What is Diffused is Called Innovation• Disease, Product, Opinion, Attitude, …

• Models• Two-Step Flow Model

1. Mass Media Inform & Influence Opinion Leaders2. Opinion Leaders Influence People within Their Communities SOCIOMETRISTS

CONTAGION

• Spread of Infectious Diseases• Passing on an Innovation via Social Ties

Social Contagion

• Diffusion Curve• Logistic S-shape

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METRICS

• Dense / Sparse Network

• Connected / Unconnected Network

• bi-Component / Components with Cut-Points or Bridges

• Larger Neighborhood Count of a Person The Earlier Adaptation of Innovation

• A Central / Marginal Position in the network

ADOPTION

• Simple Situation Innovation is Adopted (Disseminate) by an Edge, Vertex to Neighbors

• Realistic Complex Networks Different Adoptability Toward an Innovation• Receptive ≠ Reluctant

ADOPTION

Exposure•The exposure of a vertex in a network at a particular moment is the proportion of its neighbours who have adopted before that time. It may be the thought of as a chance to adopt

Thresholds •Threshold of an actor is his or her exposure at the time of adoption. It is a factual measure

Threshold Lag •A threshold lag is a period in which an actor does not adopt although he or she is exposed at the level at which he or she will adopt later.

CRITICAL MASS

The critical mass of a diffusion process is the minimum number of adopters needed to sustain a diffusion process.

Biological Metaphor A bacteria may either succeed to overcome the resistance of the human body and develop into a disease or does not gain the upper hand and is oppressed. The spread of a disease has a critical limit: once it is exceeded, the bacteria multiplies quickly