Progress 8 CI Lower
DfE Performance Tables
Lower bound of 95% confidence interval for Progress 8 score
Understanding Progress 8 Confidence Interval (Lower Bound)
This is the lower bound of the 95% confidence interval for a school’s Progress 8 score. Confidence intervals help you understand how certain we can be about a school’s true performance level.
Technical Explanation
Progress 8 scores are estimates based on the students who happened to attend in a given year. The confidence interval shows the range within which the school’s “true” underlying performance likely falls.
- If the lower bound is positive, we can be reasonably confident the school adds value
- If the lower bound is negative but upper bound is positive, the result is not statistically significant
- If both bounds are negative, the school is likely performing below average
Why This Matters
Small schools have wider confidence intervals because their results are based on fewer students. A small school with Progress 8 of +0.5 but a lower bound of -0.2 may not actually be adding more value than a larger school with +0.3 but a lower bound of +0.1.
For Technical Users
This is primarily useful for statistical analysis and comparing schools while accounting for uncertainty. For general comparison, focus on the main Progress 8 score.
Technical Details
- Column Name
- progress8_ci_low
- Data Source
- DfE Performance Tables
Coverage by School Phase
How many schools have data available for this field.
This field does not contribute to the performance score calculation.
Distribution by School Phase
Statistical distribution of values across schools.
Related Fields
Fields that correlate with Progress 8 CI Lower. Click to explore.