20 Network Experiments
- 1. Network Experiments & Interventions
- 2. 1) Assessing Peer Effects 1) Manipulate networks to force connectivity to be exogenous 1) Roommate studies 2) Natural Experiments 2) Manipulate exposure over existing networks 1) Popularity 2) Voter Turnout 2) Interventions: Use networks to affect change 1) Valente’s 4 elements of network intervention 2) Exemplars 3) Network interference in “standard” experiments 4) What we’re ignoring: small group stuff 1) network exchange experiments 2) Transmission evolution experiments
- 3. Network Experiments & Interventions Intro Shalizi & Thomas: PI is *generally* confounded General fear of confounding by unobserved selection features has pushed interest in network experiments. How to make a social relation exogenous?
- 4. Network Experiments & Interventions Problem
- 5. Network Experiments & Interventions Problem
- 6. Network Experiments & Interventions Problem
- 8. Roommates assigned randomly within gender, & self-reported smoking, study-style & messiness. No evidence of pair-similarity based on this sorting (i.e. all evidence suggests randomness is real) Network Experiments & Interventions Exogenous networks (W)
- 9. Assume that one’s one GPA is a function of own ability & peer ability and GPA Network Experiments & Interventions Exogenous networks (W)
- 10. Assume that one’s one GPA is a function of own ability & peer ability and GPA…results suggest a positive effect. Similar effects on social outcomes (joining a fraternity, etc.)… Network Experiments & Interventions Exogenous networks (W)
- 11. Network Experiments & Interventions Exogenous networks (W)
- 12. Network Experiments & Interventions Exogenous networks (W)
- 13. Network Experiments & Interventions Exogenous networks (W)
- 14. Note follow-up work (by Salganik & Watts) suggests the effects are weak and not long lasting Network Experiments & Interventions Exogenous networks (W)
- 16. Network Experiments & Interventions Exogenous networks (W) Control treatment
- 17. Network Experiments & Interventions Exogenous networks (W)
- 18. Network Experiments & Interventions Exogenous networks (W) SEPTEMBER 2010 VOL 329 SCIENCE
- 19. Network Experiments & Interventions Exogenous networks (W)
- 20. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 21. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 22. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 23. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 24. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 25. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 26. Network Experiments & Interventions Exogenous networks (W): Issues with experimental assignment Sharique Hassan
- 27. Network Experiments & Interventions Exogenous Behavior (Y) 4 types of interventions: 1) Individuals 1) Finding opinion leaders or flow blocking nodes that play a key role in the network process. usually some centrality score, or an adaptive algorithm. Here highlighted “keyplayer” nodes. 2) Segmentation 3) Induction 4) Alteration
- 28. Network Experiments & Interventions Exogenous Behavior (Y) 4 types of interventions: 1) Individuals 2) Segmentation 1) Use communities to break the groups into parts, treat some use others as controls. 3) Induction 4) Alteration
- 29. Network Experiments & Interventions Exogenous Behavior (Y) 4 types of interventions: 1) Individuals 2) Segmentation 3) Induction 1) Enhance relations & communication 4) Alteration
- 30. Network Experiments & Interventions Exogenous Behavior (Y) 4 types of interventions: 1) Individuals 2) Segmentation 3) Induction 4) Alteration 1) Programs that seek to change the shape of the network, add/remove ties or nodes
- 31. Network Experiments & Interventions Exogenous Behavior (Y)
- 32. Network Experiments & Interventions Exogenous Behavior (Y) Exploit the “Friendship Paradox” idea…
- 33. Network Experiments & Interventions conclusion Many examples of network peer effects driven by experiments. Many examples of how manipulations can change the network itself I think there’s sufficient evidence to start pushing harder against the skeptics: peer influence is clearly real; question is now how do we leverage it most effectively?