Essential Mathematics for Economics
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My textbook, Essential Mathematics for Economics, is now published and sold at Amazon. It would be nice if somebody can write a review.
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Econ Journal Watch comment leads to retraction
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Econ Journal Watch (EJW) is one of my favorite journals, which publishes critical comments. I have published one myself.
While browsing past issues of EJW, I came across this comment, which documents that the 2017 Accounting Review article of Bird and Karolyi reports exactly identical numbers in all 11 tables as the 2015 working paper version, despite the fact that the authors switched the main specification and the robustness check between the working paper version and the published version. To this comment, Bird and Karolyi replied
we identified a potentially confusing description of our methodology, which was introduced during the final iteration of copy editing at The Accounting Review. This description conflicted with our correct and clear description of our methodology elsewhere in the published version of the paper.
Out of curiosity, I checked the original published article, and the publisher simply states
The authors acknowledged that the published version of their article misstates the use of CRSP-based index membership in the main specifications and Russell-based index membership data as a robustness test. […] However, the authors were unable to provide the original data and code requested by the publisher that reproduce the findings, as shown in the article’s tables, supporting this assertion. Accordingly, the article has been retracted.
I am glad to know that some journals do the right thing.
Number of articles on arXiv
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Since 2017 or 2018, I only post my working papers on arXiv because it is free, open to anyone (they need a referral for initial submission, though), users can download the source file, and version control is straightforward. I see no value for SSRN, though it seems to be still popular among economists. An added bonus of arXiv is that if you use Overleaf, there is an option to submit to arXiv, so the submission process is (mostly) painless.
Out of curiosity, I wanted to know how many articles arXiv publishes by year and field. It was easy to get these statistics. For instance, for economics, you can go to https://arxiv.org/archive/econ and click “Article statistics by year”.
The graph below shows the number of articles in mathematics (math), computer science (cs), physics (physics), statistics (stat), and economics (econ). Here are a few observations.
- Mathematics, physics, and statistics seem to have a common trend.
- Computer science was not special until around 2004, but since then the number of articles is growing much faster than other fields.
- Economics is still very small but is growing more rapidly than other fields (except computer science).
- There seems to be a slight increase in the number of articles in 2020, likely because people had more time to do research during the pandemic or because it became popular to write papers on COVID.
CapitalOne Quicksilver 0% intro APR (2)
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In my post, I mentioned I opened the CapitalOne Quicksilver Card because it offered 0% intro APR for 15 months (and the card has no annual fee and gives 1.5% cash back on all purchases).
I have been using the card for about half a year, and so far I am very happy. In particular, I paid my federal and state income taxes using the card, so I essentially deferred the tax payment by one year, interest-free. (The IRS charges 1.75% fee for paying taxes with a credit card, but because the card gives 1.5% cash back, it is nearly offset.) I highly recommend the card to anybody. If you open an account by clicking this link, you will receive an extra sign up bonus.
On illegal immigrants
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If a person enters my house without my permission, I suppose I have the right to ask the person to leave, and if they refuse, I may force them to do so. By analogy, if a person crosses the border into a country without permission from the government of that country, I suppose the government has the right to ask the person to leave, and if they refuse, they may force them to do so. Therefore, I see no problem that some government cracks down illegal immigration and attempts to deport illegal immigrants (although there may be exceptions on an individual basis, for example children that were taken to the country by their illegal immigrant parents and grew up for quite some time, losing tie to their country of birth). It is just common sense that follows from the fundamental principle of a liberal society that honors property rights. A corollary of this argument is that I do not understand why some people (typically the radical left or whatever they are called) organize protests against the crack down of illegal immigration.