Description
fittedEndogenous = intercept+sum(instrument*coefficient).
Instrumental-variable and moment calculations compare supplied regressors, instruments, residuals and first-stage quantities. A local moment or relevance statistic does not establish exclusion, exogeneity, identification or a complete estimator.
fittedEndogenous = intercept+sum(instrument*coefficient).
When to use this tool
Use Two Stage Least Squares One Fitted Value Term when checking one supplied first-stage or moment contribution.
How to use the tool and how it works
- Enter instruments, firstStageCoefficients, intercept. Keep parallel arrays aligned. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read fittedEndogenous. Use the output convention below.
Require equally long instruments and firstStageCoefficients. fittedEndogenous = intercept+sum(instrument*coefficient).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| instruments | Instruments | Required. Array of finite number; maximum items 256. |
| firstStageCoefficients | First Stage Coefficients | Required. Array of finite number; maximum items 256. |
| intercept | Intercept | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| fittedEndogenous | Fitted Endogenous | Required. Finite number. |
{
"input": {
"instruments": [
2,
3
],
"firstStageCoefficients": [
0.5,
2
],
"intercept": 1
},
"output": {
"fittedEndogenous": 8
}
}Limitations and assumptions
- This is one first-stage fitted row, not a fitted model or complete two-stage least-squares estimator. Coefficients, instruments and their validity are supplied.
- 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
Fit an appropriate full model and examine identifying assumptions and diagnostics before interpreting an IV result.
References
Similar or alternative tools
- Weak Instrument First Stage Partial Ratio
Calculate nested first-stage partial R-squared and an ordinary homoskedastic partial F statistic from supplied sums of squares.
- Instrument Relevance One Moment Gap
covariance = meanProduct-instrumentMean*regressorMean; gap = covariance-referenceCovariance.