1. Tie Strength

2. Strong vs. Weak Ties Strong ties Trusted Close friends and family Weak ties Often part of other social circles Acquaintances, co-workers We talk about strong or weak ties, but in reality, there is a continuous spectrum

3. Mark Granovetter Foundational work in 1973, The Strength of Weak Ties Strong ties had been considered most important His work showed weak ties mattered

4. Getting a Job Carl Y. was doing commission sales for an encyclopedia firm, but was not doing well. He decided he would have to find a different job; meanwhile, he started driving a cab to bring in extra money. One passenger asked to be taken to the train station where he had to meet a friend. This friends turned out to be an old friend of Carl Y's, and asked him "what're you doing driving a cab?" When Mr. Y explained, the friend offered him the job he now holdslabor relations manager for a small company, owned by his friend. (Granovetter, 1974, p34) Granovetter, M. 1974. Getting a Job: A Study of Contacts and Careers..

5. Getting a Job George C. was working as a technician for an electrical firm, with a salary of about $8000, and little apparent chance for advancement. While courting his future wife, he met her downstairs neighbor, the manager of a candy shop, a concession leased from a national chain. After they were married, Mr. C. continued to see him when visiting his mother-in-law. The neighbor finally talked him into entering a trainee program for the chain, and arranged an interview for him. Within three years, Mr. C was earning nearly $30,000 in this business. (Granovetter, 1974, p. 49). Granovetter, M. 1974. Getting a Job: A Study of Contacts and Careers..

6. Getting a Job Edward A., during high school, went to a party given by a girl he knew. There, he met her older sister's boyfriend, who as ten years older than himself. Three years later, when he had just gotten out of the service, he ran into him in a local hangout. In conversation, the boy friend mentioned to Mr. A. that his company had an opening for a draftsman. Mr. A. applied for this job and was hired. (Granovetter, 1974, p. 76) Granovetter, M. 1974. Getting a Job: A Study of Contacts and Careers..

7. Replicating Milgrams Six Degrees Send booklets from original participants to a target, unknown person (Lin, et al) show that successful chains made heavy use of weak ties

8. Weak Ties in Use Racial integration in schools Job satisfaction in psych hospital

9. The benefits of weak ties Connect people to different social circles, exposing them to more information Many more of them in a persons life than strong ties

10. Measuring Tie Strength Time Emotional Intensity Intimacy Reciprocal Services

11. Measuring Tie Strength Additional Features Social Distance Structural Emotional Support

12. Quantifying Measurements Time Emotional Intensity Intimacy Reciprocal Services Social Distance Structural Emotional Support

13. Measurement Overlaps

14. Network Structure – Strong Ties

15. Network Structure – Forbidden Triad

16. Network Structure - Bridges

17. Tie Strength and Propagation Strong ties – more trusted Weak ties – wider spread