Although scientists state many reasons that make sharing data difficult [Tenopir et al 2011], there are many good reasons to share data. Sharing data keeps us honest and improves peer review and mutual validation [Corbyn 2012; Krugman 2013; Baggerly and Coombes 2009]. In addition, scientific data has tremendous value, so much so that new government policies declare data "an asset for progress" [Holdren 2013]. Keeping it to yourself is questionable practice when it is funded by taxpayers that much prefer to see those assets fuel innovation than rot (quite literally) in a lab. Another reason is the increased reputation and citation of research when datasets become available [Piwowar et al 2007].

Despite the recent trend to establish data sharing policies by publishers, funding agencies, and other institutions, the practice of data sharing is far from ideal [Savage and Vickers 2009].

[Tenopir et al 2011] "Data Sharing by Scientists: Practices and Perceptions."
Carol Tenopir, Suzie Allard, Kimberly Douglass, Arsev Umur Aydinoglu, Lei Wu, Eleanor Read, Maribeth Manoff, and Mike Frame. PLoS ONE 6(6): e21101. doi:10.1371/journal.pone.0021101

[Corbyn 2012] "Misconduct is the main cause of life-sciences retractions." Zoë Corbyn, Nature, 1 October 2012.

[Krugman 2013] "The Excel Depression." Paul Krugman, The New York Times, April 19 2013.

[Baggerly and Coombes 2009] "Deriving chemosensitivity from cell lines: Forensic bioinformatics and reproducible research in high-throughput biology." Keith A. Baggerly and Kevin R. Coombes. Annals of Applied Statistics, Volume 3, Number 4, pp. 1309-1334, 2009.

[Holdren 2013] "Increasing Public Access to the Results of Scientific Research." John Holdren, Memorandum of the US Office of Science and Technology, 22 February 2013. Available from https://petitions.whitehouse.gov/response/increasing-public-access-results-scientific-research

[Piwowar et al 2007] "Sharing Detailed Research Data Is Associated with Increased Citation Rate." Heather A. Piwowar, Roger S. Day, Douglas B. Fridsma. PLoS ONE 2(3): e308. doi:10.1371/journal.pone.0000308

[Savage and Vickers 2009] "Empirical Study of Data Sharing by Authors Publishing in PLoS Journals." Caroline J. Savage and Andrew J. Vickers. PLoS ONE 4(9): e7078. doi:10.1371/journal.pone.0007078