in 2012, law professors christopher buccafusco and paul j. heald performed tests of three key justifications of copyright extension, namely: that public domain works will be underutilized and less available, will be oversaturated by poor quality copies, and poor quality derivative works will harm the reputation of the original works. they compared works from the two decades surrounding 1923 made available as audiobooks. they found that copyrighted works were significantly less likely to be available than public domain ones, found no evidence of overexploitation driving down the price of works, and that the quality of the audiobook recordings did not significantly affect the price people were willing to pay for the books in print. heald's later experiment analyzing a random sample of newly-posted works on amazon.com revealed that public domain works from 1880 were posted at double the rate of copyrighted works from 1980.