PORTLAND — Oregon’s overall education system received a C, and ranked among the lowest in the country on efforts to improve teacher quality, according to a report released Wednesday.

Education Week, a nationally distributed publication, issued Oregon the rating based on grades in four categories. Oregon received no grade higher than a C-plus, which came for the state’s testing system, curriculum goals and public release of data on schools, and was still below the national average of B-minus.

The state also earned a C-plus, the national average, for a variety of issues classified as “school climate,” including parental involvement, class size, school size and school facilities.

But Oregon scored dismally on teacher quality, earning a “D,” and was singled out for not requiring professional development for teachers.

The report — “Quality Counts 2006: A Decade of Standards-Based Education’’ — issued each state overall grades based on statistics from the last 10 years. The overall national average was a C-plus, putting Oregon just below the curve.

Researchers with Education Week did credit Oregon for its academic standards, a roadmap of what students should learn at each grade level, noting that the American Federal of Teachers had rated Oregon’s standards as “clear, specific and grounded in content in all of the four core subjects and at nearly every grade span.’’

An official of the state Department of Education said the results weren’t a surprise, given the state’s budget difficulties since the turn of the century.

“Overall, our achievement was middle of the pack, which is what you’d expect after four years of instability,’’ said Gene Evans, spokesman for the department. He said work is under way to address some of the questions, fostered by a $1.75 million grant late last year from the Gates and Meyer foundations.

The plan to address some of the concerns outlined in the report about the testing system and teacher quality includes requiring closer examination of test scores to see where students in lower-performing schools need the most help. There are also plans for what Pat Burk, chief policy officer at the state Education Department, has called “a clear and focused professional development program for teachers.’’

Implementing such a plan for schools where students are consistently missing testing goals, though, could cost between $10 million to $20 million during a fiscal biennium, Burk has estimated.

Burk has said agency staff plan to make a request for such a school improvement fund in the 2007-09 legislative session.

Schools superintendent Susan Castillo has also called for major changes in the high school standardized test taken by Oregon 10th-graders, known as the Certificate of Initial Mastery, or the CIM.

Castillo has said she’d rather see high school diplomas mean more to colleges and employers, perhaps requiring students to pass a test in order to earn one, a practice that’s already in use in 25 other states.

ON THE NET: www.edweek.org/qc06