Description
Use min(0,observedReturn-targetReturn) and divide its square by observations.
Risk and sensitivity terms depend on return units, horizon and model structure. A covariance contribution or local price approximation describes only part of a portfolio or instrument's risk and does not establish a safe investment.
Use min(0,observedReturn-targetReturn) and divide its square by observations.
When to use this tool
Use Downside Deviation One Return Term when you need one explicit risk or sensitivity term.
How to use the tool and how it works
- Enter observedReturn, targetReturn, observations. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read shortfall, squaredContribution. Use the output convention below.
Require positive integer observations. Use min(0,observedReturn-targetReturn) and divide its square by observations.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| observedReturn | Observed Return | Required. Finite number. |
| targetReturn | Target Return | Required. Finite number. |
| observations | Observations | Required. Safe integer; minimum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| shortfall | Shortfall | Required. Finite number. |
| squaredContribution | Squared Contribution | Required. Finite number. |
{
"input": {
"observedReturn": -0.05,
"targetReturn": 0,
"observations": 10
},
"output": {
"shortfall": -0.05,
"squaredContribution": 0.00025000000000000006
}
}Limitations and assumptions
- The divisor is all supplied observations under this convention, not just shortfall observations. This is one contribution, not the square-root downside deviation or a complete Sortino ratio.
- 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
Use the complete portfolio or instrument model, including covariance consistency, nonlinear effects and scenario analysis. Verify scaling and estimation assumptions before interpreting a partial term as total risk.
References
Similar or alternative tools
- Sharpe Risk Free Frequency Consistency Term
Convert annual effective rate through expm1(log1p(rate)/periods); subtract from period return and divide by period volatility, then multiply by sqrt(periods) for annualized Sharpe.
- Asset Correlation Covariance Unit Crosswalk
Multiply correlation by volatilities for covariance, then by both scales.