This 10 year study of 440 Illinois school district's with high schools (serving over 1 million students) has proven a consistent and statistically significant correlation between superintendent in-district longevity and student achievement. Using ACT test scores in math and reading the study controls for poverty level, district size and location. Superintendent longevity trends, demographics, and correlations will be shared based on the first total population study of its kind conducted with a common assessment for the entire duration of the study.