To test the idea, they obtained data from the National Science Foundation on the number of researchers per capita in each state, and then randomly selected research papers that contained the phrase "test* the hypothes*". Those papers were characterized as either confirming (positive result) or rejecting (negative result) the hypothesis. To link the papers to the geographic data, the researchers used the address of the corresponding author, who is responsible for getting the paper to the journal and answering any further inquiries on it.
The end conclusion of the analysis is that "those based in US states where researchers publish more papers per capita were significantly more likely to report positive results, independently of their discipline." In other words, as local competition increases, the fraction of papers that confirmed a hypothesis went up.
via arstechnica.com