1. Tejas Channagiri 08-Jun-16
Network Simulations
Tejas Channagiri
08-Jun-16

2. Let’s start with something familiar
Structural holes
Information, control and timing advantages (Burt, 1992)
But what happens when everyone tries to play broker?
People are strategic in their networking efforts
Alters too are strategic

3. Buskens and Van de Rijt (2008)
“What happens when everyone strives for structural holes?”
In other words, what are the “macro-structural consequences of strategic social networking at the micro-level?”
Balanced complete bipartite networks
No actor has a structural advantage
Dense
Actors close
Void of closure, no triadic bases of trust

4. Agent-based simulations
Understanding how micro behaviors of agents lead up to macro outcomes for the system
How the above unfolds under different combinations of parameters (a step beyond Buskens and Van de Rijt)
Let’s look at another example

5. Simulation
Using computer software to model the operation of real-world processes, systems or events (Law and Kelton, 1991)
Computational representation of an underlying theoretical logic that links constructs together within simplified worlds(Davis, Eisenhardt and Bingham, 2007)
These representations can be coded into software and run repeatedly under varying experimental conditions
Our emphasis today will be on agent-based simulations, one of many possible types of simulations

6. Agent-based simulations vs system dynamics
ABS allows us to “grow” social structures (Epstein, 2006)
ABS models macro evolution of system given micro behaviors of agents
System dynamics – how some systems variables influence other system variables
Usually specified as differential equations
Models a system as a series of simple processes with circular causality

7. Comments on agent-based simulations
Internal and external validity
Can be deterministic or stochastic
Unlike some older mathematical models, can accommodate (Epstein, 2007) –
Heterogeneity
Bounded rationality
Space and local interactions
Non-equilibrium dynamics

8. Netlogo
Let’s proceed to a tool that helps us build agent-based simulations quickly