THE NUMBERS, EXPLAINED
How to use this calculator.
Binary Brier score uses the mean squared difference between predicted event probability and observed zero/one outcome; range zero to one.
Start with your inputs
Enter predicted probabilities (fractions), observed binary outcomes (0 or 1). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Predicted probabilities (fractions) | 0,0.5,1 |
| Observed binary outcomes (0 or 1) | 0,1,1 |
A worked example
With the example inputs above, brier score is 0.083333. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Brier score | 0.083333 |
How this is calculated
Brier score
Square each probability error and average over examples.
Symbols and units
- a
- Predicted probabilities (fractions)
- b
- Observed binary outcomes (0 or 1)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Binary Brier score uses the mean squared difference between predicted event probability and observed zero/one outcome; range zero to one.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Brier score. The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Binary Brier score uses the mean squared difference between predicted event probability and observed zero/one outcome; range zero to one.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
scikit-learn model evaluation documentation ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
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