The Facebook Global Happiness Index was created by Facebook to index happiness based on the number of times people on the site use words to convey happiness (like “happy” “yay” and “awesome”) and unhappiness (“sad”, “doubtful” and “tragic”).

According to the index based on access to two years worth of anonymous “status updates”, Fridays showed a 9.7% increase in happiness compared with the worst day of the week, Monday.

Holidays such as the Fourth of July, Thanksgiving, Christmas and Halloween also make Americans happy, while days when celebrities like Michael Jackson and Heath Ledger died were recorded to make Americans sad.

The index is an attempt to say something profound based on the reports of daily life that Facebook users share with their friends. In social psychology, it is believed that word choice can reveal a person’s mood and it is a generally accepted idea.

“When people in their status updates use more positive words — or fewer negative words — then that day as a whole is counted as happier than usual,” the creator of the index, Adam D. I. Kramer, explained in a Facebook blog post unveiling the project.

Moreover, Kramer believes that the Facebook happiness index could be the first step in reorienting the nation’s sense of self-worth.

“We have tracked the economic health of the nation for a long time,” he said. “The reason we track those things is that the government is full of economists, not psychologists.”

“If we know money doesn’t buy happiness,” he asked, “why are we optimizing for money?”

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