Description
Divide endingSubsidy minus startingSubsidy by the income span for subsidyChangePerIncome.
Policy indicators relate supplied targets, dates, categories, and measured quantities. A computed gap or formatted label can describe a record without establishing policy effectiveness or a causal explanation.
Divide endingSubsidy minus startingSubsidy by the income span for subsidyChangePerIncome.
When to use this tool
Use Subsidy Phaseout Slope when you need one policy-monitoring component with the numerator, denominator, and time basis made explicit.
How to use the tool and how it works
- Enter startingSubsidy, endingSubsidy, startingIncome, endingIncome. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read subsidyChangePerIncome. Use the output convention below.
Require nonnegative subsidies and increasing income endpoints. Divide endingSubsidy minus startingSubsidy by the income span for subsidyChangePerIncome.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| startingSubsidy | Starting Subsidy | Required. Finite number; minimum 0. |
| endingSubsidy | Ending Subsidy | Required. Finite number; minimum 0. |
| startingIncome | Starting Income | Required. Finite number. |
| endingIncome | Ending Income | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| subsidyChangePerIncome | Subsidy Change Per Income | Required. Finite number. |
{
"input": {
"startingSubsidy": 1000,
"endingSubsidy": 0,
"startingIncome": 20000,
"endingIncome": 30000
},
"output": {
"subsidyChangePerIncome": -0.1
}
}Limitations and assumptions
- The slope can be positive despite the phaseout name; this is a supplied linear segment, not an actual eligibility schedule or policy recommendation.
- 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
Review the source data, full policy definition, and relevant evaluation method before interpreting the indicator.
References
Similar or alternative tools
- Marginal Revenue Discrete Step
Divide afterRevenue minus beforeRevenue by afterQuantity minus beforeQuantity.
- Policy Benefit Cost Discount Factor
Return exp(-years × log1p(annualRate)), equivalent to (1+rate)^(-years).