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Complex contagion of campaign donations

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Presented at ICCSS2016, Evanston, US

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Complex contagion of campaign donations

  1. 1. Complex Contagion of Campaign Donations CWTS, Leiden, the Netherlands ICCSS 2016, Evanston, US June 24, 2016 V.A. Traag
  2. 2. Complex contagion Complex contagion Contagion of human behaviour typically requires multiple exposures. Contagion reinforcement How does the contact structure of adopters reinforces contagion? Is ego more likely to adopt the behaviour: • when adopters know each other? (Cohesive reinforcement) • or, when adopters do not know each other? (Independent reinforcement) .
  3. 3. Complex contagion Cohesive reinforcement Only adopters from same (largest) community matter, ignore adopters from other (smaller) communities. Independent reinforcement Only number of adopting communities matter, ignore redundant adopters within community. Adopting communities (3) Adopter degree (4) Common community adopter degree (2)
  4. 4. Campaign donation LittleSis (website dedicated to tracking US elite). • Elite network (n ≈ 50 000, k ≈ 60). Family, professional, social & colleagues, alumni, club members. • Campaign donations coupled to network information. Results for presidential campaign 2008, other campaigns similar. 0 100 200 300 John McCain Barack Obama Jan Apr Jul Oct Jan Apr Jul Oct 0 2,000 4,000 6,000 8,000 2007 2008 Announces Presumptive nominee Nominated Announces Iowa Super tuesday Presumptive nominee Nominated Elected No.Donors a b
  5. 5. Donation probability 0 1 2 3 4 5 0 1 2 ·10−2 † * † † ** * Degree 0 1 2 3 4 5 † *** *** † *** * Common community degree 0 1 2 3 4 5 0 1 2 3 4 5 6 ·10−2 † † † ** † † † Communities 0 1 2 3 † † ** † † † Source diversity No Yes † † Donated previously Donationprobability a b c d e John McCain Barack Obama χ2-test of consecutive difference: ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, †p < 0.0001
  6. 6. Conditional donation probability 0 1 2 3 4 5 0 2 4 6 8 10 12 14 ·10−3 ** ** * * 0 1 2 3 4 5 † ***† † 0 1 2 3 4 5 0 1 2 3 4 5 6 7 ·10−2 *** * † Degree 0 1 2 3 4 5 † ***† ** Communities a b c d Donationprobability NoYes Donatedpreviously John McCain Barack Obama χ2-test of consecutive difference: ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, †p < 0.0001
  7. 7. Logistic regression Degree Clustering −0.0016 −0.22 −0.004 −0.55 General Donor degree Donor communities Donor source diversity Donors common community −0.042 0.43 0.25 0.068 −0.032 0.67 0.057 0.098 Not donated previously −1 0 1 2 3 Donated previously Donor degree Donor communities Donor source diversity Donors common community 3.5 0.002 0.14 0.17 0.024 3.1 0.015 0.035 0.33 0.033 Effect Donated previously a b c John McCain Barack Obama
  8. 8. Additional results Cross cutting donations • Exposure to Democratic donors may incite Republication donations. 2008: Exposure Obama donors increase donations to McCain. 2004: Exposure Bush donors increases donations to Kerry. • Exposure to both tends to reduce donations, but weak effect. Macro level Predict total money raised based on Q1 • Amount is clearly predictive (multiplier 1.8) • Number of donors not significant • Number of independent donors significant (multiplier 1.3).
  9. 9. Conclusions Theory • Use independent sources to infer population estimates (viability). • Population network externalities ⇒ independent reinforcement. • Coordination or connections important ⇒ cohesive reinforcement. • Possibly also negative effects (oppose candidate, public goods). Consequences • Recommendations: number of independent friends. • Independent reinforcement: fast across groups, slow within. • Cohesive reinforcement: fast within groups, slow across. • Fundraising: target broad audience, multiple constituencies.
  10. 10. Thanks for your attention! Questions? Traag VA (2016) Complex Contagion of Campaign Donations. PLoS ONE 11(4): e0153539. doi:10.1371/journal.pone.0153539 v.a.traag@cwts.leidenuniv.nl Twitter: @vtraag

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