The National Science Foundation (NSF), in carrying out the Obama administration's new push for greater public access to research published in scientific journals, will consider exclusivity periods shorter than the 12-month standard in the White House directive, as well as trade-offs involving data-sharing and considerations of publishers' financial sustainability. The administration's directive, announced on Friday after two years of deliberation, asks agencies that sponsor research to impose a 12-month upper limit on how long journals can hold subscription-only rights to articles describing research that was financed with federal funds. The National Institutes of Health (NIH) adopted such a requirement almost five years ago, and now all other federal agencies that spend at least $100-million a year on research and development are being given six months to draft a similar policy. The NIH announced this past November that it would soon begin enforcement by blocking the renewal of grant awards in cases where journal publications arising from the awards do not comply with its open-access rule. The NSF, the largest provider of federal money for basic scientific research after the NIH, will very likely follow the NIH in setting a 12-month period of exclusivity as its general rule. The White House science adviser, John P. Holdren, in announcing the new policy on Friday, described an expansion of public access to federally financed research as important to economic growth. Scientific research supported by the federal government spurs scientific breakthroughs and economic advances when research results are made available to innovators. Demands for open-access research have generated years of heated debate involving publishers, universities, researchers, and various advocacy groups. The NIH instituted its 12-month policy in April 2008, but only after strenuous objections from private publishing companies that fought back against an original proposal for six months. Congress has refused to pass a government-wide mandate, despite several years of attempts by some lawmakers. And only a year ago, the Obama administration appeared to have given up on the idea, after a year of studying the question. In the end, the plan outlined by Mr. Holdren does "a very good job of balancing interests" of libraries, universities, researchers, and publishers. Industry representatives appeared to agree. In a statement issued Friday, the Association of American Publishers said the new policy "outlines a reasonable, balanced resolution of issues around public access to research funded by federal agencies."