The Statistics Software Signal03 Jan 2013
Last night on Twitter, I went on a bit of a rant about statistics packages (namely Stata and SPSS). My point was not that these software packages are bad per se, but that I have found them to be correlated with bad quality science. Here is my theory why.
- When you don’t have to code your own estimators, you probably won’t understand what you’re doing. I’m not saying that you definitely won’t, but push-button analyses make it easy to compute numbers that you are not equipped to interpret.
- When it’s extremely low cost to perform inference, you are likely to perform a lot of inferences. When your first regression gives a non-result, you run a second one, and a third one, etc. This leads untrained researchers to run into multiple comparisons problems and increases the risk of Type I errors.
- When operating software doesn’t require a lot of training, users of that software are likely to be poorly trained. This is an adverse selection issue. Researchers who care about statistics enough should have gravitated toward R at some point. I also trust results produced using R, not because it is better software, but because it is difficult to learn. The software is not causing you to be a better scientist, but better scientists will be using it.
- When you use proprietary software, you are sending the message that you don’t care about whether people can replicate your analyses or verify that the code was correct. Most commercial software is closed source and expensive. We can never know if the statisticians at Stata have a bug in their code unless we trust them to tell us. Also consider researchers from schools or companies which can’t afford expensive commercial software. Should they not be able to reproduce your results?
I do think these packages are valuable can be used for good. I have used Stata and it has saved me plenty of time. My main point is that there are a number of mechanisms through which bad science can be correlated with using push-button statistics software, not that one is a direct consequence of the other.
What your statistical software says about you (to me):
- R : You are willing to invest in learning something difficult. You do not care about aesthetics, only availability of packages and getting results quickly.
- Python or JVM languages : You are a hacker who may have already been a programmer before you delved into statistics. You are probably willing to run alpha or beta-quality algorithms because the statistical package ecosystem is still evolving. You care about integrating your statistics code into a production codebase.
- Julia : You are John Myles White.
- Stata : You are an economist who doesn’t care to code your own estimators, probably because your comparative advantage lies elsewhere. Possibly you are doing sophisticated work with panel data where Stata is the only game in town. You don’t care that you can’t do proper programming because you’re not a programmer.
- SPSS : You love using your mouse and discovering options using menus. You are nervous about writing code and probably manage your data in Microsoft Excel.
- Matlab : You definitely know what you’re doing and you care about performance. You know Matlab is expensive but you aren’t the one paying for it. You live in a bubble where everyone you know uses Matlab.
- Mathematica : You are an aesthete who believes everything Stephen Wolfram says.
- SAS : You are an analyst for a large pharmaceutical company, and SAS is all you have ever known. You have a large library of custom SAS macros, so that (clearly) makes you a programmer. That anyone would want to hand-code statistical methods leaves you utterly baffled. If SAS does not ship with a particular statistical method, then it probably isn’t important. (h/t Chris Fonnesbeck)