We learned last week that Arizona colleges have a lousy graduation rate. Except it turns out our state colleges' graduation rates rank pretty well nationwide, but our for-profits, like the huge Huckster U University of Phoenix, drag down the average. This week we learn that TUSD needs lots more teachers—tons more!—than other Tucson area districts, which gives people one more reason to cluck their tongues at the district lots of people are sure is failing compared to other local districts. Except that the raw numbers only tell part of the story.

The Star has a good, long, thoughtful article about Arizona teacher shortages, local and statewide, including one of those fun, informative interactive data pages online. The story gives teacher shortage numbers for all the local districts. TUSD needs a whopping 116 teachers while Marana needs 16.5, Sahuarita needs 16, Catalina Foothills needs 3. Even Sunnyside only needs 40. It looks like the Tucson district is in the deepest of teacher shortage doo-doo compared to its neighbors. But the article leaves out one essential bit of information: the student enrollment for each district. And it leaves out another less essential but important bit of information: each district's state grade. So let's put that information into the mix and see what we find.

TUSD needs 116 teachers while Marana only needs 16.5. But TUSD has 49,000 students while Marana only has 12,500 students. If TUSD had the same student population as Marana, it would need 30 teachers. That's still almost twice as many teachers as Marana when the enrollments are evened out, but it no longer looks like there's a 7-to-1 gap between the districts. If TUSD were Foothills-sized, it would need 12 teachers. Foothills, however, only needs 4. And if TUSD were Sahuarita-sized, it would need 14 teachers. Sahuarita needs 16, so TUSD actually needs fewer teachers than Sahuarita when enrollments are considered.

I looked at districts' enrollment figures and the number of teachers they need, then figured out how many teachers each needed for every 1,000 students. There's still a significant difference. Vail needs .4 teachers per 1,000 students. Foothills needs .6. Both TUSD and Sunnyside need 2.4 teachers per 1,000 students, between four and six times more than Vail and Foothills.

Next I looked at each district's state grade. With the exception of Sahuarita, districts with the highest state grades need proportionately fewer teachers, and districts with lower state grades need more. It's not hard to figure out why. If you took a random group of people looking for teaching jobs in the Tucson area and asked where they'd most like to teach, districts like Vail and Catalina Foothills, where family income and student achievement are high, would come up more often than TUSD, where family income and student achievement are far lower. K-12 teaching is a tough job no matter where you are, but it's less stressful—and for many teachers, more rewarding—working in high rent districts, and there's a certain prestige value in saying, "Yes, I teach at (ahem) Catalina Foothills High." The high rent districts will always have an easier time finding teachers just because of who they are, not because they're doing something right and the low rent districts are doing something wrong. [Note: Flowing Wells is the exception to the rule, with its low income student population, high state grade and low number of teachers needed relative to its size.]

The table below has compiles the information for local districts.