Public education is the single most important issue on the minds of Californians as they ponder candidates and ballot measures in this election year.

Nearly twice as many likely voters cited education over immigration, the second most prominent issue, in a recent Public Policy Institute of California poll. For that reason, and because it is the largest single item in a deficit-ridden state budget, K-12 education also looms large among politicians.

When Gov. Arnold Schwarzenegger confronted the powerful California Teachers Association over school financing last year, the CTA spent tens of millions of dollars on ads depicting Schwarzenegger as being stingy with schools, driving down his once-soaring popularity and defeating his "year of reform" ballot measures. The CTA's chief bugaboo was a measure that would have weakened the state's constitutional guarantee on school spending (Proposition 98, enacted in 1988) and given the governor more authority to reduce state spending.

Schwarzenegger's would-be Democratic challengers, Treasurer Phil Angelides and Controller Steve Westly, have pledged to increase school spending. Angelides has been particularly vociferous, depicting himself as "the only candidate in this race who will fully fund education" with higher taxes.

But what does "fully fund education" mean? How much money are we really spending on public schools, are we getting our money's worth, and if not, why not? Ask those questions and you fall into a bottomless pit of conflicting numbers, evaluations of achievement, recipes for improvement, and rationalizations for failure.

Even the seemingly simplest of those questions - How much are we spending now? - is not easily answered.

Schwarzenegger takes the direct approach. His proposed budget for 2006-07, due for revision next month, puts total spending on K-12 education in California at $66.2 billion, including $40 billion from the state budget, $12 billion in local property taxes, $1 billion from the state lottery, $7.5 billion in federal funds, $1.5 billion in local taxes to service school bonds and a few miscellaneous amounts. With a little over 6 million in K-12 enrollment, that works out to just under $11,000 per kid, a fairly impressive number.

Others take that arithmetic, multiply $11,000 by 30 kids in a classroom for a total of $330,000 per year, subtract the teacher's salary of $58,000 (California's average) and ask what happened to the other $272,000. Utilities, books, janitorial services, administration, counseling, transportation? You can get a mini-argument on any of them.
But even the $11,000 figure is not universally accepted, especially when it comes to comparing California spending with other states.

The U.S. Census Bureau just released a new report on K-12 school spending for the 2003-04 fiscal year that pegs California's at $60.4 billion and $7,748 per pupil. That's right on the mark for California's own overall figure for that year but over $1,800 per pupil less than the $9,576 that the Schwarzenegger administration calculates was spent in 2003-04. The reason? Mostly differing methodologies about counting students.

By the Census Bureau's methodology, California's per-pupil spending in 2003-04 was in 26th place, about $500 under the national average of $8,287, well below top-ranked New Jersey's $12,981, but well above bottom-ranked Utah's $5,008.
If that weren't confusing enough, the National Education Association, which includes CTA, did its own rankings for 2003-04, placing the national average at $8,807 and California at $7,860 - nearly $1,000 lower, in 33rd place. That's the figure that advocates of higher school spending often cite (although Angelides has been claiming California is 43rd).

So what would "fully fund" mean? Would it mean meeting the Proposition 98 guarantee, which would leave California's status relative to other states virtually unchanged? Would it mean reaching the national average, which would cost $3 billion to $6 billion a year, depending on what number one accepts as the national average? Or would it mean matching New Jersey and other top-top spending states, which would cost about $30 billion more? And would more money produce better results? Let the debate begin.