Twenty-eight states require disclosure of hydraulic fracturing chemicals. Twenty-three states direct reporting to FracFocus; additionally, companies in other states use this registry. FracFocus contains the most comprehensive dataset on fracturing chemicals but faces data quality and transparency criticisms. In response, FracFocus announced upgrades, and since May 2015, publishes aggregated data. We used Linux and R version 3.2.0 to clean and analyze 96,449 forms submitted between March 9, 2011 and April 13, 2015 for accuracy, completeness, and timeliness. We characterize data, and compare results to state law and industry practice, to suggest how to induce more accurate and complete disclosures. We find that rates of withheld chemical information have increased since 2013, and appear unaffected by different legal requirements. However, when companies report fracturing chemicals without attribution to the specific products in the fracturing fluid (a "systems approach" to reporting), withholding rates drop four-fold. State deadlines shortened reporting timelines, but compliance rates are low absent indication states will enforce. Automatic field population and prompts in FracFocus can reduce data error, while enforcement signals, education, and harmonized requirements may boost compliance and enhance disclosure. Systems reporting should occur, with states retaining authority to request product-specific ingredient lists. (C) 2015 Elsevier Ltd. All rights reserved.