Stata 15

Stata 15 was released on June 6, 2017 and I got my copy three days later. The big news is that it includes support for Markdown and dynamic documents through three new commands: dyndoc, putpdf and putdocx. It also has a markdown command to convert Markdown to HTML.

How do these tools compare with markstat? Obviously the main difference is that the new commands are part of official Stata, whereas markstat relies on Pandoc and, for PDF targets, on a LaTeX installation. On the other hand, markstat has a simpler syntax and provides additional functionality via Pandoc, the most important of which is the ability to generate HTML, PDF and DOCX output from the same input script.

Here are my first impressions.

1. Cleaner Scripts

Stata’s dyndoc uses the following syntax for code blocks

sysuse auto, clear
summarize mpg

Note the use of both a Markdown code fence ~~~~ and a dynamic tag <<dd_do>>. In contrast, markstat relies on a simple “one tab or four spaces” indentation rule

    sysuse auto, clear
    summarize mpg

An alternative to allow more control, such as hiding Stata code, is to specify the strict option and use code fences

    sysuse auto, clear
    summarize mpg

I believe this leads to more readable input scripts, much in the spirit or Markdown itself. Checkout this comparison with Stata’s dyndoc example The difference is more noticeable in complex documents with lots of code.

Also, markstat lets you introduce Mata code blocks using an m instead of an s in the code fence. For an example see Mata matters.

2. Nicer Output

Compare the HTML output of dyndoc using the previous two commands

. sysuse auto, clear
(1978 Automobile Data)

. summarize mpg

    Variable |        Obs        Mean    Std. Dev.       Min        Max
         mpg |         74     21.2973    5.785503         12         41

With the output from markstat

. sysuse auto, clear
(1978 Automobile Data)

. summarize mpg

    Variable │        Obs        Mean    Std. Dev.       Min        Max
         mpg │         74     21.2973    5.785503         12         41

Just a cosmetic issue, but markstats HTML output is more in line with PDF output.

3. Inline Code

Inline code in dyndoc uses a dynamic tag:

The average fuel efficiency is <<dd_display: %4.2f `r(mean)'>>.

The equivalent markstat code is a bit less obtrusive and easier to type

The average fuel efficiency is `s %4.2f r(mean)`.

Moreover, markstat supports inline Mata code using an m instead of an s. (This is also the syntax of R markdown, which uses an r.)

4. Metadata

markstat takes advantage of Pandoc’s support for metadata, using a simple three-line syntax for author, title and date (which may be inline code):

% Literate Data Analysis
% Germán Rodríguez
% `s c(current_date)`

markstat also supports more general YAML blocks. For more information see metadata.

5. Bibliographies

Thanks again to the amazing Pandoc, markstat supports citations. The basic idea is to prepare a BibTeX file with the references. You can then cite them in the text, for example typing @knuth84 to refer to his literate programming paper. The bib option of markstat will arrange for Pandoc to format the citations, look them up in the BibTeX database, and generate a list of references at the end of your document, in a style of your choice. For example Knuth’s paper will appear in the default Chicago style as

Knuth, Donald. 1984. “Literate Programming.” The Computer Journal 27 (2): 97—111.

For a quick example see citations. A more extended example is provided by my Stata Journal paper introducing markstat, Check out this page to access the source code of the paper, the BibTeX database used to resolve the references, and the resulting HTML and PDF versions.

6. PDF Output

I think a big advantage of markstat is that it can generate a PDF file from the same input script, admitedly at the expense of needing a LaTeX distribution. But once you have jumped the installation hurdle, all you do is add the pdf option, as explained in the original paper.

The dyndoc command generates HTML only. There is a new putpdf command, but this is really a lower-level command; it provides a lot of control, but seems aimed more at programmers than regular users. Compare typing the text

You can *italicize*, ~~strikeout~~, <u>underline</u>, sub/super script~2~

with writing the commands

putpdf text ("You can ")
putpdf text ("italicize, "), italic
putpdf text ("strikeout, "), strikeout
putpdf text ("underline"), underline
putpdf text (", sub/super script")
putpdf text ("2 "), script(sub)

A comparison of markstat with putpdf using the example in the Stata announcement may be found here.

For longer examples, you can see both the input script and the HTML and PDF output for my papers on the wfs and markstat commands, as well as the markstat version of my Stata tutorial.

7. Word Documents

markstat 2.0 and higher can also generate a Word document from the same input script using the docx option. As noted above, dyndoc can generate HTML only*. There is a new putdocx command, but again this is really a lower-level command; it provides a lot of control but at a price, compare typing the script

You can *italicize*, ~~strikeout~~, <u>underline</u>, sub/super script~2~

which by the way is exactly the same as in 6 above, with writing the commands

putdocx text ("You can ")
putdocx text ("italicize, "), italic
putdocx text ("strikeout, "), strikeout
putdocx text ("underline"), underline
putdocx text (", sub/super script")
putdocx text ("2 "), script(sub)

A comparison of markstat with putdocx using the example in the Stata announcement may be found here. Another example using the proverbial fuel efficiency data may be found here. Please note that the docx option works best with Pandoc 2.0 or higher.

*Update. Stata 16 added a docx option to dyndoc, so it can generate a Word document from a Markdown script with Stata dynamic tags. There are also improvements to putdocx and new commands html2docx and docx2pdf for converting across formats.

8. Dynamic Presentations

markstat 2.0 and higher can also generate HTML presentations using the S5 engine, or PDF presentations via LaTeX using Beamer, all thanks to the amazing Pandoc. You use metadata to specify the title, author and date of the presentation, which are used to generate a title slide. You then author your slides using Markdown for your narrative, including bullet points which can be shown incrementally, and Stata code and results. For an introductory example see dynamic presentations.

Stata 15 has no equivalent commands. It is possible to author your slides directly in HTML or LaTeX and embed Stata code and results using Stata 15’s dyntext, but then you have to deal with the complexity of writing HTML or LaTeX code instead of simple Markdown.

Also, markstat uses the same script for both output formats, and the new nodo option lets you tinker with your presentation, and change engines and/or themes, without having to rerun the analysis. (Hat tip to Ben Jann, who provides a nodo option in texdoc) Finally, the new bundle option lets you produce self-contained HTML presentations, with all graphs as well as ancillary CSS and JavaScript files included in the document using base64 encoding. Beamer presentations are always self-contained.

9. R Code

Not a relevant comparison here, but in addition to Stata and Mata code, markstat lets you use R code, both in fenced blocks and inline. For an example see a comparison of how Stata and R compute quantiles.

Updated for markstat 2.0