Georgia education leaders unveiled a new measure of school efficiency Thursday that compares performance to cost.

The Financial Efficiency Star Rating uses expenditures per pupil and the state Department of Education's school report card, known as the College and Career Ready Performance Index, to establish a star rating of one to five, with one being the worst and five the best.

The numbers are based on a three-year average of per-pupil spending versus scores on the index, which is largely driven by results on state standardized tests, currently the Milestones.

In core metro Atlanta, the Gwinnett County Public Schools achieved the best score, 4.5, and Atlanta Public Schools the worst, 1.5. Forsyth County, beyond the Perimeter but still in metro Atlanta, had the best score in the state, scoring the only 5 out of all 180 districts. Forsyth scored well for academics but also was among the 10 districts with the lowest cost per pupil, at $7,115 averaged over three years. Atlanta, however, had the second highest cost in the state, at $13,297 per student.

Fulton County Schools fared nearly as badly as Atlanta while DeKalb County Schools and Decatur City Schools were below average. The Cobb County School District did alright, but Marietta scored poorly.

View system ratings at ccrpi.gadoe.org: Choose a school district, then select a report for elementary, middle or high school. Click on the "Financial Efficiency" tab to find the overall district rating, which is displayed in each of the three report types. Some districts responded to the scores, explaning the causes of their results.

Education officials were required by state law to develop the rating system, and explain here how they calculated the results.