Enter and die at the same time

Stata does not allow a subject enters the risk set and dies at the same time, here is an explanation:

http://www.stata.com/support/faqs/stat/zerohelp.html

Human interface device

Sometimes not all tray icons show up (after a new boot). This can be caused by a unexpected stop in the human interface device. Re-start that service and reboot the computer should solve the problem.

Some R related materials

I have been leaning toward R gradually. Here are some useful resources in learning and using R:

http://faculty.chicagogsb.edu/peter.rossi/research/bayes%20book/bayesm/Making%20R%20Packages%20Under%20Windows.pdf

http://www.maths.bris.ac.uk/~maman/computerstuff/Rhelp/Rpackages.html

http://www.bioconductor.org/workshops/2006/biocintro_oct/lectures/R_intro.pdf

A good GUI for R is JGR: http://rosuda.org/JGR/

Weather

It is getting cooler here in Beijing. Hopefully Hangzhou will be cool off in the next half month so that we can fully enjoy our bike trip between Hangzhou and Suzhou.

Stata 10 graphics editor, bad idea!

The new graphics editor provided in Stata 10, to me, is a bad idea. Instead of focusing on trying to get the figure right in a do file, many people, especially beginners, will take shortcuts and rely heavily on the new editor. This, in long run, is a very bad idea. Once people start to do that, they lose the capability to be able to replicate exactly what they do. If you spend 10 minutes editing a figure, then realize the data is not quite right and need to run the figure command again, then you need another 10 minutes to edit it... you get the idea.

It is a bit disappointing to find that unicode support is still not there. I have been waiting for this for too long...

aML reported random effects

The random effects that aML reports are standard deviation and correlation, not variance and covariance.

Age, period, and cohort effect

A model with age, period, and cohort can only be identified if:

1) Two or more of the remaining age, period, or cohort coefficients to be equal;
2) Use a proxy variable approach that assumes the cohort (e.g. cohort size) or period effects are proportional to certain measured variables;
3) Transform at least one of the age, period, or cohort variables so that its relationship to other is nonlinear.

A piecewise linear hazard rate model can usually be identified because of (3).

Ideal calender solution

The combination of Google calender, Mozilla Sunbird (or Thunderbird + Lightning), and Google calender provider (https://addons.mozilla.org/en-US/sunbird/addon/4631) provides an ideal calender solution. More details can be found here: http://www.linux.com/feature/118068.

My working paper

My most recent working paper "Does Son Preference Influence Children's Growth in Height? A Comparative Study of Chinese and Filipino Children" is available online:
http://www.ccpr.ucla.edu/ccprwpseries/ccpr_018_07.pdf

Another one (impact of famine on mortality) will be available soon.