Description
Subtract actual from forecast for forecast-minus-actual, or reverse the subtraction for actual-minus-forecast.
Signed errors preserve direction while absolute or squared errors emphasize magnitude. Their gradients and small-residual approximations represent specific mathematical terms rather than complete performance evaluations.
Subtract actual from forecast for forecast-minus-actual, or reverse the subtraction for actual-minus-forecast.
When to use this tool
Use Metrics: Forecast Error Sign Convention when you need an explicit error, gradient, or local loss component.
How to use the tool and how it works
- Enter actual, forecast, convention. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read result. Expand result to inspect the returned fields.
Subtract actual from forecast for forecast-minus-actual, or reverse the subtraction for actual-minus-forecast.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| actual | Observed value on the same scale and unit as its prediction. | Required. Finite number. |
| forecast | Forecast value on the same scale and unit as actual. | Required. Finite number. |
| convention | Convention | Required. Text; one of "forecast-minus-actual", "actual-minus-forecast". Implementation limit: 8192 Unicode code points and 16384 UTF-16 code units. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| result | Result | Required. Object. |
| result.error | Error | Calculated result member: number. |
{
"input": {
"actual": 3,
"forecast": 5,
"convention": "forecast-minus-actual"
},
"output": {
"result": {
"error": 2
}
}
}Limitations and assumptions
- The convention controls the sign only; error magnitude, aggregation, and measurement units are unchanged.
- Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Assess a full error distribution and keep the sign and aggregation conventions consistent across models.
References
Similar or alternative tools
- Metrics: Forecast Error Underprediction Weight
Use residual = actual minus forecast.
- Forecast Delta Revision One Horizon
Return revised minus previous as revision and calculate both old and new forecast-minus-actual errors.