The Oregon Education Association called on teachers to take part in a “Day of Action” May 8th 2019. Unlike other states that have had teacher walkouts recently protesting low wages, Oregon teachers were pushing for funding to lower student to teacher ratios, and to gain more support staff such as counselors and nurses. This was in response to a budget proposal that would have meant layoffs of an estimated 900 teachers. If I were to tell you there is little correlation between education spending and educational outcomes, you might think twice before blindly supporting the increase in a budget. Such is the case if we look at 2017 education expenditures versus average fourth and eighth grade NAE reading and math scores, or high school graduation rates (Figures 1-4 shown below-Oregon is marked by the green dot). Oregon ranks in the middle of the pack for 4th grade reading and 8th grade math and reading scores. It does poorly in other rankings: seventh in 4th grade math scores, and it had the second worst graduation rate in 2017.

Does Oregon need more teachers?
Oregon had the fifth highest student to teacher ratio for the average of the 2014-2015, 2015-2016, and 2016-2017 school years combined. Figures 5 and 6 show public high school graduation rates and 4th grade reading scores show a weak negative correlation with student to teacher ratio (but the correlation coefficients are larger than those found using total expenditures). Utah, Arizona, Nevada, and California were the only states to have higher pupil:teacher ratios. Utah, with the third highest average pupil:teacher ratio for 2014-2017, still achieved a graduation rate higher than the national average (86% vs 84.74% national average) and 4th grade math scores higher than the national average (242 vs 221.24).

How is Oregon doing compared to other states?
Federal, state, and local expenditures combined (not including capital outlay, debt service, etc.), Oregon’s per student expenditure is 19th highest (Figures 7 and 8). It could (and probably should be argued) that we should not just look at the total expenditure, but also the cost of living index since the value of money in each state differs. In that case, Oregon’s per student expenditure ranks 38th. That said, state average per student expenditure (federal + state + local funding) adjusted for cost of living index has a weakly positive correlation with graduation rate. Those states with pupil:teacher ratios higher than Oregon (Nevada, Arizona, Utah, and California) are also low for adjusted per student expenditure. Utah’s above average high school graduation rate again looks impressive since it had the third lowest per pupil spending adjusted for cost of living.

Oregon spends around 59% of its education spending on instruction; close to the national average of 60%. Is Oregon paying teachers too much money and that is why we have the fifth highest pupil:teacher ratio? Oregon ranked 11th highest in teacher’s salary for FY: 2017, so it does seem a little high except when adjusted for cost of living (Figures 9-11). When divided by the cost of living index, Oregon drops to seventh lowest in teacher salary. If we want to take Utah as an example of a state using its money efficiently (shown with the red dot), it is paying teachers higher than Oregon when adjusted for cost of living, and spending a higher percentage of its total education expenditures on instruction (63%), so it doesn’t seem to be the case that teachers in Oregon are being paid too much. Instructional spending has a weak positive correlation with high school graduation rate, so this may play a small role in student achievement.

The demographics of Utah are not the same as Oregon, so it may not be a good comparison. For instance, Utah has a lower percentage of non-Caucasian students (Figure 12). These students have historically tended to fare poorly in graduation rates (for reasons not mentioned in this article).

Conclusions

States’ student performance by NAE reading and math scores and high school graduation do not correlate strongly with any single factor of expenditure even when adjusted for cost of living. There are likely so many factors at play, that the strongest factors will only have weak correlations, but general trends are in the expected directions (higher spending = higher performance). Adjustments for cost of living did improve correlations. My educated guess is there is likely a stronger correlation between family income adjusted to cost of living, but looking at a state level cost of living index seems too large a scale. It would surely be more useful if the data was at a more local level (income:local cost of living ratio). Also, a median cost of living or some type of income inequality measure might be a better metric. The highest correlations with outcomes were with teacher to pupil ratio and percent non-Caucasian. A more detailed analysis broken down by county, district, or even by school may be able to elucidate the most important factors, but that data is hard to obtain. If nothing else, this analysis has convinced me that standardized data sets should be more easily available to the public.

Other correlations attempted: