“…one of the things we’re doing to fuel … more private sector innovation and discovery,” said President Barack Obama is to make the vast amounts of America’s data open and easy to access for the first time in history.”

That aspirational goal is one that countries around the world have taken on as their own over the past four years. Globally, officials are increasingly viewing open data as fundamental to democratic governance and development. That growth has naturally promoted new scrutiny and questions about what open data is and who benefits from its release.

“This comes at a time when there are significant doubts around the world about outcomes and best practices,” said John Wonderlich, policy director for the Sunlight Foundation, in an interview. “The White House’s new policies make clear that we don’t have all the answers, but there are ways forward, towards new data and better processes.”

Last week, Slate published my article exploring why a new executive order to open up federal government data is a big deal.

The article generally presents the new executive order and associated open data policy in a generally positive light, with one significant caveat: its effect upon or relevance to government transparency.

The focus that the President and his advisors have taken on “open data” is squarely upon entrepreneurship, innovation, and scientific discovery, not “transparency,” an issue his administration has faced substantial — and growing — criticism over after a promising start to his first term.

“Creating transparency and accountability through new technology won’t be achieved through a single policy, or just through cultural change or political commitments,” said Wonderlich. “What was so reassuring about this announcement is that the White House is still working on all of those areas. There are certainly some still missing, or some areas where the White House is less accountable, or more secretive (money in politics and national security still come to mind immediately) but this demonstrates that “open data,” if that phrase is to have lasting meaning, will evolve through a complex policy process.”

Steven Aftergood, however, questioned whether making government data open and machine-readable would have an effect on government secrecy, particularly in the intelligence world. Aftergood, the director of the Project on Government Secrecy at the Federation of American Scientists, has been a long-time observer and critic of the culture and machinery of secrecy in the federal government.

A second caveat, which wasn’t in my Slate article, comes with respect to the inclusion of a warning about the so-called “mosaic effect” in the open data policy.

This effect, which originates in the intelligence world, describes a situation in which multiple pieces of data and information that are meaningless (or at least harmless or unclassified) on their own could be combined and analyzed to discover the identities of people, sensitive locations or other secrets.

That official consideration left journalists and open government advocates worried.

OpenTheGovernment.org praised aspects of the open data policy but expressed concern about potential exemptions from disclosure because of the mosaic effect. Scholars and journalists have long been concerned that the mosaic theory has been used to deny Freedom of Information Act requests.

Read “Mosaic Effect” definition here: project-open-data.github.io/policy-memo/#i… & tell me that wouldn’t lengthen review process & expand potential for denial.

— Derek Willis (@derekwillis) May 9, 2013

While architects of Data.gov and former US CIO Vivek Kundra have acknowledged concerns about the mosaic effect in the past, formal articulation in the policy is a new wrinkle.

In answer to my question about this precise concern at a press conference at the FOSE Conference in Washington last week, US CIO Steven VanRoekel said that nothing in the executive order or in the open data policy would allow the federal government to restrict the release of information requested under the Freedom of Information Act.

Federal agencies will “still follow FOIA to the letter,” said VanRoekel. “Nothing about executive orders and policy changes law.”

Whether or not this new policy is used to restrict sensitive information will be seen in the months and years ahead. In the meantime, concern is probably better focused upon the dangerous parallel the Department of Justice is making between espionage and investigative journalism.