# http://www.fakereceipt.us

Ever wanted to build fictitious bills to illustrate something in your econ classes? This is the website you’ve been looking for: http://www.fakereceipt.us.

# Classquestion.com, the free alternative to IClicker

I wanted to make my 100+ students class a little more interactive this Fall. So I looked into live Q&A tools.

The most famous one is IClicker. But I thought it was overpriced and I didn’t not want  my students to have yet another thing to pay for.

Then, I discovered classquestion.com.

Classquestion can be accessed from any browser, both on smartphones and on computers. I’ve tried it in class with my students and it works like a charm so far. There are still a couple of functionalities that could be added (such as the possibility to include a TA for your class, or a full-fletched and seamless Canvas integration), but it really does most of what IClicker does.

What is more: it is completely free and relies on a donation-based business plan.

So I figured I’d make a little donation and save my students the cost of IClicker. It’s hard to evaluate how much money that saved them because IClicker has different pricing schemes and students may use ICliker in different classes. But if students want to use the IClicker app, the cost is around $20 per year (cheaper options involve buying a remote, which to my knowledge do not expire, …. until a new version of the remote comes up and is required by a teacher). So I guess I saved my 100+ students a total or anywhere between$500 and $2000 this semester? # Basic arithmetic in Latex More and more, I use Latex as scratch paper, sometimes to develop numerical (counter-)examples. I often find it much cleaner and better organized than if I rely on actual pen and paper. Numerical examples are usually a “back and forth” kind of business, with many moving parts. You have to find the numbers that “make it work here” without “changing things there”. So finding the right combination of numbers often requires a lot of simple (but error-prone) calculations. In that matter too, Latex can save you time and prevent mistakes. With pen and paper, you would usually (a) write down your arithmetic (e.g., (1/3)*57 + (1/4)*23 + (5/12)*20), (b) use a calculator or spreadsheet to perform the calculation, and (c) write down the result on your sheet of paper. There are many ways to make mistakes and loose time in that process. As often, Latex offers a solution. Have a look at https://tex.stackexchange.com/questions/30081/how-can-i-sum-two-values-and-store-the-result-in-other-variable. Very much like you would if you were using Markdown, Latex — with the help of a particular package — lets you, (a) write down your arithmetic and (b) simply ask your computer to calculate the result. The code looks something like this: \documentclass{article} \usepackage[nomessages]{fp}% http://ctan.org/pkg/fp \begin{document} \FPeval{\result}{clip( (1/3)*57 + (1/4)*23 + (5/12)*20 )}$(1/3)*57 + (1/4)*23 + (5/12)*20 = \result$\end{document} As illustrated in https://tex.stackexchange.com/questions/30081/how-can-i-sum-two-values-and-store-the-result-in-other-variable, you can easily round decimals to your liking: \documentclass{article} \usepackage[nomessages]{fp}% http://ctan.org/pkg/fp \begin{document} \FPeval{\result}{round( 100/3, 1 )}$100/3 = \result\$

\end{document}

# p-hacking (and other data manipulations) made mainstream?

I am not a big fan of the last part of the talk that is too optimistic about randomized control trials and may make then look like some sort of panacea. RCTs have important limitations, especially when it comes to external validity. If you run enough of them, you are bound to find the kind of patterns Laura Arnold seems to criticizes using the 15 ingredients study (7:20 in the video). What works here now might not work there tomorrow. Eventually, you need structural models and sound theory to understand when a treatment works, and when it does not.

That’s the curse of the TED format. Arnold is somewhat critical of the format, but she has to fit in it. I am sure she and the organizations she advocates for know of the limits of RCTs. But there’s only so much you can say in 18 minutes if you want to conclude on an uplifting note.

Still, the overall message is very much worth spreading. It’s important to popularize notions like p-hacking and file drawer effect that rarely even make it into introductory statistics class. And it’s nice to see TED being a little critical of itself (or rather TEDx being critical of TED).

# LanguageTool : adding words

One slightly unpleasant feature of LanguageTool with Texstudio is that new words are a little harder to add to the dictionary than when using Texstudio’s native spellcheck.

The good part of having to add words through LanguageTool is that words you add are, well, actually added to the dictionary, whereas adding words to Texstudio’s native dictionary is — in my experience — unstable (I’ve had to add the same words multiple time in many occasions, in particular after updates).

For explanation on how to add words to LanguageTool’s spell check, once again see the very good documentation on LanguageTool’s website at http://wiki.languagetool.org/hunspell-support#toc0.

I will try to keep an updated list of words I added here. The list might be of some use in particular to those working in a field related to microeconomics theory.