Notes from the Class Room

Class Notes

These notes are intended as a supplement to the powerpoint slides, and not a replacement. There are many references to figures, none of which appear in this document, and most of which are extremely helpful if not absolutely necessary in understanding the material. So the reader is strongly encouraged to keep a copy of the slides at hand while reading through these notes; and to follow the exte...

Notes on the Comparison Class

It is common (e.g. Klein 1980) to analyze sentences involving vague expressions, such as (1), as being interpreted with reference to a comparison class that serves to provide a standard of comparison. For example, (1a) might be interpreted as saying that Fred’s height exceeds the standard for some set of individuals of which Fred is a member (adult American men, 8-year-old boys, basketball play...

Quantile methods Class Notes

Asymmetric absolute loss Let us define the “check” function (or asymmetric absolute loss function). For τ ∈ (0, 1) ρτ (u) = [τ1 (u ≥ 0) + (1− τ)1 (u < 0)]× |u| = [τ − 1 (u < 0)]u. Note that ρτ (u) is a continuous piecewise linear function, but nondifferentiable at u = 0. We should think of u as an individual error u = y − r and ρτ (u) as the loss associated with u.1 Using ρτ (u) as a specificat...

Duration Models Class Notes

Duration data appear in a diversity of situations in economics, but I will often refer to unemployment duration to provide a focus for the presentation of the material. Suppose we select a random sample of N persons entering unemployment and wait until they find jobs. Then we record the number of weeks each person has been unemployed: t1, t2, ..., tN . We have observations on the duration of a ...

MAT 25A - Class Notes