Updated

Hoping to build on state-level reforms aimed at closing the education achievement gap, the Education Department opened its Race to the Top competition to school districts on Sunday, inviting the poorest districts across the country to vie for almost $400 million in grants.

Following four months of public comment on a draft proposal, the Education Department unveiled its final criteria for the district-level competition, which will award 15 to 25 grants to districts that have at least 2,000 students and 40 percent or more who qualify for free or reduced-cost lunches — a key poverty indicator.

Grants will range from $5 million to $40 million, depending on the size of the district.

"We want to help schools become engines of innovation through personalized learning so that every child in America can receive the world-class public education they deserve," Education Secretary Arne Duncan said in a statement.

The original Race to the Top competition, announced in 2009, set out to provide more than $4 billion in grants to states that undertook ambitious education reforms. Dozens of states changed laws, introduced new teacher evaluation programs and lifted caps on charter schools to qualify for a slice of the funds.

Congress approved about $550 million for Race to the Top this year, and the Education Department expects to use about $383 million of it for grants to districts that propose ambitious reforms to personalize learning, narrow the achievement gap and prepare students for college. The rest will go toward the department's early learning competition.

School districts in states that received money in previous years will still be eligible to apply. Districts can propose programs that affect all or just some of their schools, and can also band together to apply for grants. Proposals geared to specific grades or subject areas also will be considered.

To be eligible, districts must put in place evaluation systems to measure performance of teachers, principals and superintendents by the 2014-2015 school year. The Education Department also planned initially to require school board evaluations and personalized learning plans for students, but officials said they eliminated both requirements based on public objections.

It remains to be seen whether the district-level competition will be alluring enough to entice districts to enact sweeping reforms, said Michael Petrilli, executive vice president at the Thomas B. Fordham Institute, a Washington-based think tank.

"It seems that the response from the districts has been somewhat anemic, "Petrilli said. "Simply put, there's just much less money at stake than there was for the states."

School districts are expected to signal their intent to apply by the end of August, with applications due on Oct. 30. Districts will find out whether they've been selected for a grant by the end of the year.