Chris Danforth, a University of Vermont mathematician who co-led the creation of a website with fellow mathematician Peter Dodds, calculated daily happiness and unhappiness using data from Twitter, news and other data from tens of millions of people.
Hedonometer.org is based on the research of Dodds and Danforth and their team in the Computational Story Lab at the University of Vermont's Complex Systems Center, as well as the technology of Brian Tivnan, Matt McMahon and their team from MITRE, a non-profit organization, which has expertise in big data analytics.
"What it's doing right now is measuring Twitter, checking the happiness of tweets in English," Danforth and Dodds said in a statement.
Words are ranked and using these scores, the team collects about 50 million tweets worldwide each day and calculates the total average happiness score.
Soon the hedonometer will be drawing in other data streams, such as Google Trends, The New York Times, blogs, CNN transcripts, text captured by the link-shortening service Bitly and data-mining in 12 languages, Danforth said.
"Reporters, policymakers, academics -- anyone -- can come to the site, and see population-level responses to major events," Danford said.
However, there are few surprises in the findings. The happiest day each year is Christmas -- although some years are happier than others -- followed by Thanksgiving, Valentine's Day and New Year's Eve.
Unhappiest days following the Boston Marathon bombing were: the Dec. 14 massacre at Newtown, Conn., the day Michael Jackson died in 2009, the 2011 tsunami in Japan and the day the bank bailout was voted down by the U.S. House of Representatives in 2008 to permit the government purchase of up to $700 billion in mortgage-backed securities.