Today, EdSystems is releasing “Measuring Student Growth to Support Organizational Learning Using the Academic Progress Indicator (API)”, a report on the new student progress measure developed by Chicago Public Schools (CPS) as part of its Continuous Improvement and Data Transparency (CIDT) system. The API represents a significant step forward in how schools and communities can use data to understand and support student learning. Rather than focus on a proficiency level or compare growth against other students, it provides an approach to think about higher achievement over time.
Why a New Metric Is Needed
For many years, schools have been evaluated based on the percentage of students labeled as “proficient” on state tests. More recently, schools and districts have moved to using comparative growth measures such as student growth percentiles and value-added measures. While proficiency and comparative growth are important, relying on them as the main way to measure progress has fundamental flaws:
- Proficiency rates can shift without real change. When Illinois recently adjusted the bar for proficiency, school-level percentages changed overnight, even though student learning hadn’t. In addition, given how proficiency is reported, changes in proficiency rates often reflect which students enter or leave a school, not how the same group of students grows over time.
- Change in proficiency is dependent on where the cut line is set. Schools with many students clustered near the bar may see big swings in proficiency, while others show little movement even if students are making real gains.
- Comparative growth does not link growth and achievement. Students can have good comparative growth even if their achievement is declining.
Comparative growth metrics are not effective for tracking performance over time and, as researcher Andrew Ho has noted, overreliance on proficiency measures can send misleading signals about school performance and improvement. A different metric is necessary to help schools understand their students’ progress.
What Is the API?
The Academic Progress Indicator (API) is a new metric developed with CPS to track changes in student achievement over time on Illinois’ standardized state assessments. It uses a 1–99 scale called Normal Curve Equivalents (NCEs), which, unlike percentiles (another common measure of achievement), have equal intervals and can be added or subtracted. This makes it possible to:
- See whether the same students are making progress from year to year.
- Compare results across grades and subjects.
- Track achievement growth over multiple years in a clear, interpretable way.
In addition, the API for CPS is calculated using a baseline norm, meaning that all students can show improvement, and their achievement is not compared to other students in the same year.
Our Findings
Our report evaluates the development and early implementation of the API. Key findings include:
- Greater credibility and alignment. School leaders and stakeholders see the API as more useful and trustworthy than Chicago’s former system, the School Quality Rating Policy (SQRP). However, the API cannot, on its own, meet all the design principles set forth by Chicago’s accountability redesign efforts.
- Achievement growth matters. While average achievement and proficiency rates are closely related, changes in proficiency are only moderately correlated with true achievement gains—making API a stronger progress measure.
- Elementary schools are improving. CPS elementary schools show strong growth on the API, especially in grades 6–8.
- High school progress lags. CPS high schools, particularly for low-income students, show weaker. This raises important questions and points to a need for systemic solutions.
- API is most powerful in combination. Principals see potential for using API data in conversations with teachers, families, and communities, but more work is necessary to link the API to context information, such as resources and school climate. School leaders find the API especially valuable when paired with comparative growth metrics, such as effect size, that show how their students’ growth compares with peers statewide.
Why This Matters
At EdSystems, we believe that data should be used for learning, not just accountability. Standardized test results will never tell the whole story of student readiness, but they remain an important piece of the picture. The API helps schools, communities, and policymakers move beyond blunt measures of proficiency toward a more nuanced and actionable understanding of student progress.
By focusing on growth, Chicago is setting a path for accountability systems that are more transparent, equitable, and improvement-focused. We hope this work sparks broader conversations across Illinois and beyond about how to use data in ways that truly support students.
