- Associated Instructional Materials:
Question Reliability tells you how consistent and trustworthy your test questions are. Think of it like asking “If I gave this same test to the same students tomorrow, would I get similar results?” The higher the reliability, the more you can trust that your test is measuring what you think it’s measuring.
In OnTarget, when we talk about question reliability combined by subject, we’re referring to how consistent and dependable the test questions are when grouped by subject area (like Math, Reading, Science, etc.).
Understanding the Reliability Scale (Cronbach’s Alpha)
The reliability score goes from 0 to 1, like a percentage:
- 1.0 = Perfect (but rarely achieved in real life)
- 0.8-0.9 = Great – Your test is very reliable
- 0.7-0.8 = Good – Your test is reliable enough for most purposes
- 0.6-0.7 = Okay – Your test has some issues but is usable
- Below 0.6 = Problematic – Your test results may not be trustworthy
What the Chart Shows You
This bar chart displays Cronbach’s alpha reliability coefficients for questions across three academic subjects: ELA (English Language Arts), Math, and SS (Social Studies).
Social Studies: 0.8 – Excellent Work! Your Social Studies questions are working really well together. Students who know the material consistently score higher, and students who struggle consistently score lower. You can confidently use these results for grading and identifying which students need extra help.
ELA and Math: 0.6 – Needs Some Attention These subjects show “okay” reliability, which means there might be some inconsistency in your questions. Maybe some questions are too tricky, poorly worded, or don’t match what you’re actually trying to test.
Key Observations from the sample graph
Reliability Rankings: Social Studies shows the highest question reliability at approximately 0.82, followed by ELA at around 0.65, and Math at roughly 0.62. All three subjects fall within the acceptable range for research purposes (typically 0.60 and above).
Social Studies Performance: The substantially higher reliability in Social Studies (0.82) suggests that questions in this subject area produce more consistent responses. This could indicate that social studies concepts may be more stable in students’ minds or that the questions are more clearly written and less ambiguous.
Math and ELA Similarity: The relatively close reliability scores between Math (0.62) and ELA (0.65) suggest similar levels of question consistency, though both are notably lower than Social Studies.
Potential Implications
The lower reliability in Math might reflect the subject’s cumulative nature – if students lack foundational knowledge, their responses may be more variable or inconsistent. Math questions also often have definitively right or wrong answers, which could lead to more random guessing when students are uncertain.
For ELA, the moderate reliability could stem from the interpretive nature of many language arts questions, where multiple valid perspectives might exist, leading to some response variability.
What This Means for Your Classroom
When Reliability is High (like your Social Studies):
- Trust your results – Use these scores confidently for grades and parent conferences
- Identify learning gaps – Students who scored low likely need targeted help
- Keep doing what you’re doing – Your questions are well-aligned with your teaching
When Reliability is Lower (like your ELA and Math):
- Be cautious with scores – Don’t make major decisions based on one test alone
- Look for patterns – Which specific questions confused most students?
- Consider retesting – Give students another chance if scores seem off
- Review your questions – Are they clear? Do they match what you taught?
Simple Ways to Improve Reliability
Before Creating Tests:
- Match your questions to your lessons – Only test what you actually taught
- Use clear, simple language – Avoid confusing wording
- Make sure questions are at the right difficulty level – Not too easy, not impossibly hard
After Seeing Low Reliability:
- Review confusing questions – Which ones did most students get wrong?
- Check if questions align – Do they all test the same skill or concept?
- Consider throwing out “bad” questions – Sometimes it’s better to remove a confusing question entirely
- Get feedback from students – Ask what was unclear
Red Flags to Watch For
Your test might have reliability issues if:
- Good students suddenly score poorly
- Scores don’t match your daily observations of student understanding
- There’s a huge spread in scores that doesn’t make sense
- Students who usually perform similarly have very different results
Considerations for Improvement
The chart suggests that Math and ELA question sets might benefit from review to improve consistency. This could involve clarifying question wording, ensuring appropriate difficulty levels, or checking that questions truly measure the intended constructs.
Overall, while all subjects show acceptable reliability, there’s clear room for improvement in Math and ELA to reach the higher standard demonstrated by Social Studies.
✅ What does “combined by subject” mean?
It means OnTarget is looking at all questions from the same subject area across one or more assessments, and analyzing them together to calculate a reliability score for that subject.
For example:
- If you’re analyzing Math, OnDataSuite will take all the Math-related questions from an assessment (or multiple assessments), and evaluate how well those questions work together to measure student performance.
- It does the same for Reading, Science, etc.
📊 How is reliability calculated?
OnTarget often uses statistics like:
- Cronbach’s Alpha – Measures internal consistency. Higher values (closer to 1) mean the questions are more reliable.
- Point-biserial correlation – Measures how well each question differentiates between high and low performers.
The Bottom Line
High reliability means you can trust your test results and use them to make important decisions about student learning and your teaching. Low reliability means you should dig deeper, ask more questions, and maybe give students another way to show what they know.
Remember: A reliable test helps you help your students. When you can trust your assessment results, you can better identify who needs extra support and who’s ready to move ahead.