The efforts they underwrite run from the mundane—translating school district materials into Spanish, for instance—to activities deeply intertwined with policy, such as providing information to parents on topics like teacher evaluation and school choice.

Since 2005, the Bill & Melinda Gates Foundation has donated or pledged some $5.2 million in grants to Stand for Children's Leadership Center, including a two-year, $3.5 million grant in 2010 focused primarily on its teacher-quality work. The Eli and Edythe Broad Foundation provided $500,000 in startup costs to StudentsFirst and has funded Education Reform Now to the tune of $2 million since 2008.

And beginning in 2010, the Walton Family Foundation has supported all three of those advocacy organizations, including $2.5 million for Stand for Children, $1 million to StudentsFirst, and $2.4 million to Education Reform Now, which is associated with the political action committee Democrats for Education Reform.

(The Gates and Walton foundations also provide grant support to Editorial Projects in Education, the nonprofit corporation that publishes Education Week.)

'Echo Chamber'

The confluence of foundation funding to those education advocacy groups has raised concerns among critics, who ask whether such donations amount to working in lockstep to influence policy. The groups have similar positions on some key policy issues, such as the expansion of charter schools and the development of teacher evaluations based in part on student test scores."Because of the amount of money that is available, each of these funded groups wields this ability to speak very, very loudly," said Kevin G. Welner, a professor in the school of education at the University of Colorado at Boulder. "And because of the sheer number of aligned and interlocking groups, they form a strong network and echo chamber."

For their part, foundation officials say they are trying to seize a critical moment of national interest in education policy.

"Stand for Children has deep reach that really lines up with some of the foundation's other significant investments," said Debbie Veney Robinson, a spokeswoman for the Seattle-based Gates Foundation. "What they do are things that we don't do as an organization—galvanizing parents and educating parents about education issues, working with community groups."

In addition, the groups "are bringing more horsepower to education reform advocacy, especially through outreach efforts—recruiting, acclimating, motivating more advocates," said Ed Kirby, a senior program officer for the Walton Family Foundation, in Bentonville, Ark. "Our view is that we've got great advocates doing strong work, but it is still a very undeveloped movement, relative to where it could be and should be."

The Walton Family Foundation's primary goal through its grantmaking is to promote policy attention to school choice, from charters to vouchers to tax credits, Mr. Kirby said. Both StudentsFirst and Education Reform Now support private school choice to a degree.

The Gates Foundation's most recent grant to Stand for Children, meanwhile, focuse