4.3 readme files and data dictionaries

When naming files we embed metadata into our file naming conventions to encode relevant information for the reader. But we can only store so much information in a file name. So we also include three additional files:

  • A _README file which resides in our root folder and elaborates on the contents of our folder structure.
  • A _README file that resides in our data directory and discusses some of the particulars of the how, where, and who did the actual data collection.
  • A _DATA-DICTIONARY file that also resides in our data directory and elaborates on how our data is stored and organized.

These files - containing a brief description of the major folder contents, naming conventions, and data structure - are critical for transparency and reproducibility because they allow others to easily understand the contents of your directory and data without needing to ask you. This is especially helpful when working with a group or sharing directories with others.

General rules

A readme file and data dictionary should:

  • Exist in at least two locations, the root directory and the data directory.
  • Be prepended with an underscore "_". This will push these files to the top of the directory for easy access.
  • _README and _DATA-DICTIONARY files should be in all caps, so they really stand out; this should be the first thing you look at when looking at any directory or folder, as this is your guide to its contents.

File formats

Readme files and data dictionaries should be written in plain text, for this will ensure that the files describing your project can be opened on any computer. You will often see readme files called _README.txt or _DATA-DICTIONARY.txt.

Our example readme and data dictionaries use a plain text format called markdown.


We recommend that you create your readme files as markdown, a way of formatting plain text files, allowing us to provide additional meaning to our content. For example, in plain text, if we want to emphasize content, we don’t really have a way of doing this. In markdown, we can use italics and bolding if needed. We can also create lists and tables.

Learn the basic syntax of markdown here.