​People love speed, especially when you really need to look up something or change a file in a hurry. You do not want to see the computer is always in responding mode when you click something. For me, I have a mac mini at home. It is a 2014 mac mini with a 8 GB 1600 MHz DDR3 memory, a 2.6 GHz Dual-Core Intel Core i5 processor, and a 1 T hard disk drive (HDD).

It was OK for the first few years. However, it became slower and slower. It takes me 5-10 mins to start and 30-40 mins when there is a system update. And it could not respond when I handle large data in R or STATA. So I decided to add an external hard drive (SSD) to improve the speed. About the difference between HDD and SSD, you can find it here. Generally, SSD is much faster than HDD. However, SSD is more expensive with a relatively small storage size. Recent Mac models, from desktops to laptops, are all using SSDs. If you have Mac model with fusion drive, you can simple consider it as a mixture of HDD and SSD. Anyway, in the following, I show you how to do it in a quick way.

-Choose your SSD
Portable external SSD has a small size. Currently, a 500 GB SSD is around 90 dollars (maybe you can find a better deal). Simply choose one you like (brand/color/shape) and we will go to the next step.

-Format your SSD
It is essential to format your SSD before using it, because you want it to have the same format with your Mac. In your computer, find out "Disk Utility", plugin your new SSD, you can find it appears in the on the left column. Select it, then click "erase" (PLEASE SELECT THE NEW SSD NOT YOUR MAC DISK!!! YOU DO NOT WANT TO ERASE ALL YOUR CURRENT FILES). If you are using the latest MacOS(Catalina), you need to choose the format "APFS". It takes 1 min to erase and format. After this, your SSD is ready to go.

-Copy your stuff from old to new
There are several ways to setup your new SSD. You can simply install a brand new system and get everything re-start. For me, I have a lot stuff in my old computer, so I have to transfer them to the new one. One way is to use the Apple's time machine to backup. The way I use here is pretty simple. You can download a software called "SuperDuper", which supports to copy everything including the system, all the computer settings, documents etc. in tor the SSD. The copy process took 3 hours for me. And it is really depends on the condition of your current computer and the size of your files.

For full post please find here.

The Commons, the newest building at Tulane University, is a $55 million, 77,000-square-foot state-of-the-art eatery and study area, which opened Fall 2019. To celebrate, Tulane Official Instagram account promoted a #AtTheCommons photography contest. 
My photo is one of the two final winners. You can find the post here.

Package "RStata" provides a way to combine Stata code with R. This might be a quick way to turn Stata knowledge into R environment.  The example results are as follows. For installation, please see my note on Github (Mac User).

I will create a repository at github for causal analysis.
This repository provides useful econometric tools for causal analysis and program evaluation. It contains files (mostly markdown files) and notes that I benefit a lot during my study. Updating daily.

If you are using Mac OS Catalina Beta Version released in June 2019, you might probably have difficulty in opening Anaconda, which appeared as above under beta system.
Following is a way that I used to solve this issue (if you installed the Mac OS beta version on all of your PCs like me and still need to learn/use):
In Terminal, install Jupyter with pip; then open Jupyter notebook through Terminal/ working under vscode with respect interpreter
```
pip3 install jupyter
​jupyter notebook
```
​It will promote to Jupyter Notebook in your web browser.
VS code can also be used after select repected interpreter and you can begin using #%% comment as following:

References are available here.

Details with latex code see here.
For most Ph.D. students in economics, latex is the most widely used document preparation system. This note provide one technique in preparing tables.
Here we need a package called "colortbl".
And the tables can be showed as follows: