Model Estimation and Analysis: Linear Regression Models

Least squares regression

  • Least squares
  • Instrumental variables and 2SLS
  • Least absolute deviations with bootstrapped standard errors
  • Forward stepwise regression
  • Extreme accuracy
    • Condition number and variance inflation factors
    • Leverage values

Summary statistics

  • Fit measures, F, R2, adjusted R2, sum of squares
  • Information criteria
  • Likelihood function
  • Durbin-Watson
  • Condition number for data matrix

Predictions and residuals

  • List, plot, retain
  • Standardized residuals
  • Influence analysis, leverage values, diagonals of ‘hat’ matrix
  • Confidence interval for predictions
  • Fill missing values 

Robust estimation

  • White and heteroscedasticity adjusted covariance matrix
  • Newey-West estimator
  • Cluster corrected covariance matrix
  • Least absolute deviations - bootstrapped covariance matrix
  • Nonparametric kernel density regression

Panel data

  • Analysis of variance and covariance
  • Fixed effects
  • Random effects
  • Random parameters (GLS, hierarchical)
  • Balanced or unbalanced panels
  • Autocorrelation correction
  • Heteroscedasticity and autocorrelation tests
  • LM and Hausman tests for effects
  • White and Newey-West robust estimators
  • Dynamic linear models (Arellano/Bond)

Heteroscedasticity

  • Weighted least squares
  • Multiplicative heteroscedasticity, maximum likelihood
  • Goldfeld-Quandt, Breusch-Pagan tests
  • Groupwise heteroscedasticity
  • Heteroscedastic fixed and random effects
  • ARCH, GARCH, GARCH in mean

Specification tests

  • CUSUM
  • Omitted variables
  • Structural change
  • J, Cox, PE tests

Restrictions

  • F and Wald tests for linear restrictions
  • Restricted regression
  • Inequality restricted regression
  • Wald tests for nonlinear restrictions
  • Lagrange multiplier, likelihood ratio tests

Autocorrelation

  • Durbin-Watson, Godfrey tests
  • ML, Prais-Winsten, Cochrane-Orcutt, Hildreth-Lu estimators
  • Hatanaka estimator for lagged dependent variable, 2SLS
  • Higher order autoregressive

Systems of linear equations

  • 2SLS
  • 3SLS
  • Seemingly unrelated regressions
    • Autocorrelation
    • Heteroscedasticity
    • Singular equation systems with constraints
    • GLS and maximum likelihood
  • Cross and within equation constraints
  • Covariance structures
    • OLS, GLS
    • Panel corrected standard errors
    • Grouping of observation units
    • Autocorrelation

Example

Linear regression of Household Income on Age, Eduction and Marital Status for women with a residual plot.

+----------------------------------------------------+
| Ordinary    least squares regression               |
| Model was estimated Feb 26, 2007 at 11:40:30AM     |
| LHS=HHNINC   Mean                 =   .3374391     |
|              Standard deviation   =   .1582045     |
| WTS=none     Number of observs.   =       2625     |
| Model size   Parameters           =          4     |
|              Degrees of freedom   =       2621     |
| Residuals    Sum of squares       =   58.02916     |
|              Standard error of e  =   .1487954     |
| Fit          R-squared            =   .1164220     |
|              Adjusted R-squared   =   .1154106     |
| Model test   F[  3,  2621] (prob) = 115.12 (.0000) |
| Diagnostic   Log likelihood       =   1278.393     |
|              Restricted(b=0)      =   1115.937     |
|              Chi-sq [  3]  (prob) = 324.91 (.0000) |
| Info criter. LogAmemiya Prd. Crt. =  -3.808843     |
|              Akaike Info. Criter. =  -3.808843     |
| Autocorrel   Durbin-Watson Stat.  =  1.0247658     |
|              Rho = cor[e,e(-1)]   =   .4876171     |
+----------------------------------------------------+
+--------+--------------+----------------+--------+--------+----------+
|Variable| Coefficient  | Standard Error |b/St.Er.|P[|Z|>z]| Mean of X|
+--------+--------------+----------------+--------+--------+----------+
 Constant|    -.04835445       .02662990    -1.816   .0694
 AGE     |     .00180144       .00034102     5.282   .0000   45.8411429
 EDUC    |     .02087183       .00169078    12.345   .0000   10.3082433
 MARRIED |     .10791838       .00751798    14.355   .0000    .81600000