Time Invariant Variables and Panel Data Models : A Generalised Frisch-Vaugh Theorem and its Implications

Mundlak (1978) showed that when individual effects are correlated with the explanatory variables in an error component (EC) model, the GLS estimator is given by the within. In this paper we bring out some additional interesting properties of the within estimator in Mundlak’s model and go on to show that the within estimator remains valid in an extended EC model with time invariant variables and correlated specific effects. Adding an auxiliary regression to take account of possible correlation between the explanatory variables and the individual effects, we find that not only the elegant results obtained by Mundlak but also the above mentioned special features carry over to the extended case with interesting interpretations. We obtain these results using a generalised version of the Frisch-Waugh theorem, stated and proved in the paper. Finally, for both the EC models with and without time invariant variables we have shown that the estimates of the coefficients of the auxiliary variables can also be arrived at by following a two-step procedure.panel data, error components, correlated effects, within estimator.

Going Beyond Functionings to Capabilities : an Econometric Model to Explain and Estimate Capabilities

Any attempt to operationalise the capability approach necessitates an adequate framework for the measurement of the abstract unobservable multidimensional concept that the term human development stands for. One such attempt is the latent variable approach including principal components, factor analysis and MIMIC models. The first two models provide estimates of the latent variables but are silent on the factors influencing these variables (capabilities in our context). MIMIC models represent a step further in this direction as they include exogenous “causal” variables for the latent factors but the effects go only in one direction i.e. from the “causes” to the latent variables. We argue that some of these causal factors not only influence human development but they are also influenced by it and that unless this feedback mechanism is taken into account we do not have a complete picture of this complex phenomenon. In this paper we present a theoretical framework incorporating the above aspects into a coherent system of causes, effects and interactions, leading to an econometric model which represents a generalisation of existing latent variable models. Estimating the model will enable us to explain the level of capabilities, say how they can be best improved, test our theoretical hypotheses and derive estimators that reflect the actual capabilities rather than just the functionings.human development, capability approach, latent variables, qualitative response, simultaneous equations.

The Canon Wars

Canons are taking their turn down the academic runway in ways that no one would have foretold just a decade ago. Affection for canons of construction has taken center stage in recent Supreme Court cases and in constitutional theory. Harvard Dean John Manning and originalists Will Baude and Stephen Sachs have all suggested that principles of “ordinary interpretation” including canons should inform constitutional interpretation. Given this newfound enthusiasm for canons, and their convergence in both constitutional and statutory law, it is not surprising that we now have two competing book-length treatments of the canons—one by Justice Scalia and Bryan Garner, Reading Law, and the other by Yale Law Professor William N. Eskridge, Interpreting Law. Both volumes purport to provide ways to use canons to read statutes and the Constitution. In this Review of Interpreting Law, we argue that this contemporary convergence on canons raises some significant interpretive questions about judicial power and the very idea of a canon