Tweeting how you feel 

 Benedict Carey of the New York Times  discusses  a  paper  (gated) by Scott Golder and Michael Macy showing that people's moods -- as expressed within the character limit of twitter -- have remarkably predictable patterns.  The authors' interpretation is that our moods are fundamentally linked to our circadian rhythms. 


 First, I really like this paper and I'm glad to see it come out in Science.  An earlier version was presented at one of the conferences put on by Arthur Spirling and the Harvard Program on Text Research, and it caught my eye then. 

 On one hand, it's obviously innovative research that is making great use of the reams data that are now sitting in the interwebs somewhere, waiting to be analyzed.  The possibilities in this new, data rich realm are seemingly endless:  the  culturomics/ngrams  project, work on political blogs ( Abe Gong ),  congressional tweeting  (Drew Conway), the  news cycle  (Leskovec, Backstrom, and Kleinberg), and so on. 

 But we also should spend more time stepping back and asking hard questions about the data.  Are tweets really a great measure of sentiment if the decision to tweet isn't random?  Who is online and how do they differ from the offline folks?  There is basically no discussion of this in the Golder and Macy article.  Perhaps the lack of attention to the limitations of "big data" research is just an inevitable part of the  fad cycle , but that doesn't mean we should let our standards slide just because someone has cool data.