What are the best place to learn more twin studies and
the "DID"
methodology ?
On twin studies, a good review is offered by the American Society of
Human Genetics statement entitled "Recent Developments in Human
Behavioral Genetics: Past Accomplishments and Future Directions". It
was published in _American Journal of Human Genetics_ 60:1265-1275,
1997. I've attached a pdf version of the article below.
The most relevant section of the article is entitled "twin and
adoption studies". In this section, identical and fraternal twin
studies are discussed---their assumptions, benefits and problems. The
article offers the example of schizophrenia for which identical
vs. fraternal twin studies nailed down that a big component of the
condition is genetic. The article outlines how the leverage comes
from the fact that the correlation between identical twins reflects
all of the genetic variance whereas that between fraternal twins
reflects only half of the (additive) genetic variance.
There is a large and growing literature in Difference in Difference
research designs. A relatively straightforward overview is offered
in:
@Article{
author = {Meyer, Bruce D.},
title = {Natural and Quasi-experiments in Economics},
journal = {Journal of Business and Economic Statistics},
year = 1995,
volume = 13,
number= 2,
pages = {151--161}
}
I don't have a PDF of this article.
The MIDTERM EXAM will cover material from day one of the class up to
and including sampling.
Cheers,
JS.