Assess Students Statistical Understanding with LOCUS
ThinkData Ed is now the official home of the Levels of Conceptual Understanding in Statistics (LOCUS) assessments, a research-backed system transforming how students’ understanding of statistics is measured and supported.
A Conceptual Way to Assess Statistical Thinking
While most assessments focus on whether an answer is correct or incorrect, LOCUS was built to reveal how students think statistically and how their understanding develops over time.
Designed for use from middle school through introductory college statistics, LOCUS assessments help educators and researchers gain meaningful insight into students’ conceptual understanding, not just their procedural skills.
Nearly 25% of questions in the SAT math section are comprised of statistics & data-related items. LOCUS has had an impact on the way statistical understanding is measured on many state and national standardized assessments.
Explore the LOCUS Platform
Official LOCUS
Contact ThinkData Ed to learn more about the different tests students could take.
Discount codes are available for teachers who share the resource with their students.
Sample Items
Browse 100+ assessment items, including constructed response and multiple-choice questions, each with explanations, commentary and insights into the thinking behind student responses.
Build a Test
Create a free custom assessment tailored to your classroom or research needs by selecting from LOCUS sample items. These items are not part of the official LOCUS assessments and access reports that align with national standards.
Grounded in Research and Practice
LOCUS assessments are aligned with many state and national standards as well as the Guidelines for Assessment and Instruction in Statistics Education (GAISE) framework.
Each test balances emphasis across the four major stages of statistical problem solving:
| Stage | Focus Areas |
|---|---|
| Formulating Statistical Questions | 10–20% |
| Collecting Data | 20–30% |
| Analyzing Data | 25–35% |
| Interpreting Results | 25–35% |
These proportions ensure every LOCUS assessment captures the full process of statistical reasoning.
Who LOCUS is For
LOCUS is designed for:
- Teachers who want meaningful assessment data to guide instruction
- District leaders and curriculum specialists seeking valid, reliable measures of statistical literacy
- Researchers evaluating interventions and instructional outcomes
- Educators that want to give students a reliable predictor of their AP Statistics exam preparedness
Start using LOCUS today to strengthen how students think, reason, and communicate with data.
“I have loved being able to use the LOCUS test to not only guide my instruction but to measure the hopeful effectiveness of my teaching.”
– Cindy Finley, Introduction to Data Science Teacher