Search Results for: christakis fowler

Controversy over the Christakis-Fowler findings on the contagion of obesity

Posted on by

Nicholas Christakis and James Fowler are famous for finding that obesity is contagious. Their claims, which have been received with both respect and skepticism (perhaps we need a new word for this: “respecticism”?) are based on analysis of data from the Framingham heart study, a large longitudinal public-health study that happened to have some social network data (for the odd reason that each participant was asked to provide the name of a friend who could help the researchers locate them if they were to move away during the study period.

The short story is that if your close contact became obese, you were likely to become obese also. The long story is a debate about the reliability of this finding (that is, can it be explained by measurement error and sampling variability) and its causal implications.

This sort of study is in my wheelhouse, as it were, but I have never looked at the Christakis-Fowler work in detail. Thus, my previous and current comments are more along the lines of reporting, along with general statistical thoughts.

We last encountered Christakis-Fowler last April, when Dave Johns reported on some criticisms coming from economists Jason Fletcher and Ethan Cohen-Cole and mathematician Russell Lyons.

Lyons’s paper was recently published under the title, The Spread of Evidence-Poor Medicine via Flawed Social-Network Analysis. Lyons has a pretty aggressive tone–he starts the abstract with the phrase “chronic widespread misuse of statistics” and it gets worse from there–and he’s a bit rougher on Christakis and Fowler than I would be, but this shouldn’t stop us from evaluating his statistical arguments. Here are my thoughts: Continue reading →

Christakis response to my comment on his comments on social science (or just skip to the P.P.P.S. at the end)

Posted on by

The other day, Nicholas Christakis wrote an article in the newspaper criticizing academic social science departments: The social sciences have stagnated. . . . This is not only boring but also counterproductive, constraining engagement with the scientific cutting edge and … Continue reading →

Difficulties of using statistical significance (or lack thereof) to sift through and compare research hypotheses

Posted on by

Dean Eckles writes: Thought you might be interested in an example that touches on a couple recurring topics: 1. The difference between a statistically significant finding and one that is non-significant need not be itself statistically significant (thus highlighting the … Continue reading →

Controversy over social contagion

Posted on by

Dan Engber points me to an excellent pair of articles by Dave Johns, reporting on the research that’s appeared in the last few years from Nicholas Christakis and James Fowler on social contagion–the finding that being fat is contagions, and so forth.

More precisely, Christakis and Fowler reanalyzed data from the Framingham heart study–a large longitudinal study that included medical records on thousands of people and, crucially, some information on friendships among the participants–and found that, when a person gained weight, his or her friends were likely to gain weight also. Apparently they have found similar patterns for sleep problems, drug use, depression, and divorce. And others have used the same sort of analysis to find contagion in acne, headaches, and height. Huh? No, I’m not kidding, but these last three were used in an attempt to debunk the Christakis and Fowler findings: if their method finds contagion in height, then maybe this isn’t contagion at all, but just some sort of correlation. Maybe fat people just happen to know other fat people. Christakis and Fowler did address this objection in their research articles, but the current controversy is over whether their statistical adjustment did everything they said it did.

So this moves from a gee-whiz science-is-cool study to a more interesting is-it-right-or-is-it-b.s. debate. Continue reading →