Montgomery County and neighboring Fairfax trade bragging rights annually on dozens of measures of achievement. But on a basic measure of cost, Fairfax consistently wins.

For the 2009-10 school year, the cost per pupil in Montgomery County was nearly $15,500, up from about $8,500 in 1999-2000. In Fairfax County, the cost was about $12,900, up from $8,200 a decade earlier.

The differences are less about the cost of special student needs and more about the cost of teacher salaries.

Both districts have about 12 percent of their students enrolled in programs for nonnative English speakers, requiring additional staff and support. Montgomery has a slightly higher percentage of low-income students -- about 27 percent compared with Fairfax's 23 percent. But Fairfax has more students labeled in need of special educational support -- 14 percent compared with 12 percent in Montgomery.

Weast's results More than 11 years after taking charge of the Montgomery County schools, Superintendent Jerry Weast's reforms have earned him a solid "I" for incomplete. "> SAT scores Graduating class mean score (math/reading) participation 1999 1096 79% 2009 1077 74% 2010 1105 67% Advanced Placement exams Year Number taken Pass rate 1999 7,167 83% 2009 28,575 72% Graduation rate 1999: 91% 2007: 90% 2008: 89% 2009: 87% Maryland Standardized Assessments (MSAs) Third grade Year Math pass rate Reading pass rate 2003 75% 67% 2009 71% 87% Eighth grade Year Math pass rate Reading pass rate 2003 57% 74% 2009 67% 89%

The striking difference is in the average teacher salary. In Fairfax, it's about $64,700. The average Montgomery teacher earns more than $10,000 more per year, or about $76,500. And while that difference contributes to at least the appearance of financial efficiency, Fairfax Federation of Teachers President Steven Greenburg warns it might haunt the school system in future years.

"You're saving money, but you're also risking not attracting the best employees," he said.

In fact, the starting salary has been bumped down by $800 over the past two years so that second-year teachers feel they still have something on rookies, Greenburg said.

"That could be cost effective, but I look at it as devaluing your work force."