Qualitative coding for computer scientists.

Qualitative coding is a form of feature extraction in which text (or images, video, etc.) is tagged with features of interest. Sometimes the codebook is defined ahead of time, other times it emerges through multiple rounds of coding. For more on how and why to use qualitative coding, see Emerson, Fretz, and Shaw's Writing Ethnographic Fieldnotes or Shaffer's Quantitative Ethnography.

Most of the tools available for qualitative coding and subsequent analysis were designed for non-programmers. They are GUI-based, proprietary, and don't expose the data in well-structured ways. Concepts from computer science, such as trees, sorting, and filtering, could also be applied to qualitative coding analysis if the interface supported it. Furthermore, a command-line based tool can be combined with other utilities into flexible pipelines.

Qualitative Coding, or qc, was designed to address these issues. I have used qc as a primary coding tool in a SIGCSE paper on packaging and releasing a stable version was my own dissertation work. qc is in active use on forthcoming publications and receives regular updates as we need new features.

• Due to its nature as a command-line program, qc is only well-suited to coding textual data.
• qc uses line numbers as a fundamental unit. Therefore, it requires text files in your corpus to be hard-wrapped at 80 characters. The corpus import task can handle this for you.
• Coding is done in a two-column view in a variety of supported editors, including Visual Studio Code, vim, and emacs. If you are not used to using a text editor, or if you prefer a more graphical coding experience, qc might not be the best option.

pip install qualitative-coding

Choose a working directory for your project. Run qc init -y. This will create settings.yaml with the default settings, and set up the required files and directories for you. (Visual Studio Code is the default editor.)

qc is designed to give you a powerful terminal-based interface. The general workflow is to use code to apply qualitative codes to your text files. As you go, you will start to have ideas about the meanings and organization of your codes. Use memo to capture these.

Once you finish a round of coding, it's time to reorganize your codes. Edit codebook.yaml, grouping the flat list of codes into a hierarchy. Use codes stats to see the distribution of your codes. Use codes rename if you want to rename existing codes.

After you finish coding, you may want to use your codes for analysis. Tools are provided for viewing statistics, cross-tabulation, and examples of codes, with many options for selecting and filtering at various units of analysis. Results can be exported to CSV for downstream analysis.

The --coder argument supports keeping track of multiple coders on a project, and there are options to filter on coder where relevant. More analytical tools, such as inter-rater reliability, are coming.

Create a new directory somewhere. We will create a virtual environment, intstall qc, and download some sample text from Wikipedia.

$ python3 -m venv env
$ source env/bin/activate
$ pip install qualitative-coding
$ qc init -y
$ curl -o what_is_coding.txt "https://en.wikipedia.org/w/index.php?title=Coding_%28social_sciences%29&action=raw"
$ qc corpus import what_is_coding.txt

Now we're ready to start coding. This next command will open a split-window session in your editor of choice; add comma-separated codes to the blank file on the right. Once you've added some codes, we can analyze and refine them.

$ qc code chris
$ qc codebook
$ qc codes list
- a_priori
- analysis
- coding_process
- computers
- errors
- grounded_coding
- themes

Now that we have coded our corpus (consisting of a single document), we should think about whether these codes have any structure. Re-organize some of your codes in codebook.yaml. When you finish, run codebook again. It will go through your corpus and add any missing codes.

$ qc codes list
- analysis
- coding_process
    - a_priori
    - grounded_coding
- computers
- errors
- themes

I decided to group a priori coding and grounded coding together under coding process. Let's see some statistics on the codes:

$ qc codes stats
Code                  Count
------------------  -------
analysis                  2
coding_process            7
.  a_priori               2
.  grounded_coding        2
computers                 2
errors                    1
themes                    2

stats has lots of useful filtering and formatting options. For example, qc codes stats --pattern wiki --depth 1 --min 10 --format latex would only consider files having "wiki" in the filename. Within these files, it would show only top-level categories of codes having at least ten instances, and would output a table suitable for inclusion in a LaTeX document. Use --help on any command to see available options.

Next, we might want to see examples of what we have coded.

$ qc codes find analysis
Showing results for codes:  analysis

what_is_coding.txt (2)
================================================================================

[0:3]
In the [[social science|social sciences]], '''coding''' is an analytical process | analysis
in which data, in both [[quantitative research|quantitative]] form (such as      | 
[[questionnaire]]s results) or [[qualitative research|qualitative]] form (such   | 

[52:57]
process of selecting core thematic categories present in several documents to    | 
discover common patterns and relations.<ref>Grbich, Carol. (2013). "Qualitative  | 
Data Analysis" (2nd ed.). The Flinders University of South Australia: SAGE       | analysis
Publications Ltd.</ref>                                                          | 
                                                                                 | 

Again, there are lots of options for filtering and viewing your coding. At some point, you will probably want to revise your codes. You can easily rename a code, or collapse codes together, with the rename command. This updates your codebook as well as in all your code files.

$ qc codes rename grounded_coding grounded

At this point, you are starting to realize some of the deeper themes running through your corpus. Capturing these in an "integrative memo" is an important part of qualitative coding. memo will open a preformatted document for you in vim.

$ qc memo chris --message "Thoughts on coding process"

Congratulations! You have finished the first round of coding. Before you move on, this would be an excellent time to check your files into version control. I hope you find qc to be powerful and efficient; it's worked for me!

-Chris Proctor

Use --help for a full list of available options for each command.

Initializes a new coding project. If settings.yaml is missing, writes the settings file with default values. Make any desired edits, and then run qc init again. You can skip this step by passing --accept-defaults (-y) to the first invocation of qc init. It is safe to re-run qc init.

$ qc init

Checks that all required files and directories are in place.

$ qc check

Opens a split-screen vim window with a corpus file and the corresponding code file. The name of the coder is a required positional argument. After optionally filtering using common options (below), select a document with no existing codes (for this coder) using --first (-1) or --random (-r)

$ qc code chris -1

Save and close your editor when you finish. In the unlikely event that your editor crashes or your battery dies before you finish coding, your saved changes are persisted in codes.txt. Run qc code --recover to resume the coding session.

Ensures that all codes in the project are included in the codebook. (New codes are added automatically, but if you accidentally delete some while editing the codebook, qc codebook will replace them.)

$ qc codebook

List all coders in the current project.

Opens your default editor to write a memo, optionally passing --message (-m) as the title of the memo. Use --list (-l) to list all memos.

$ qc memo -m "It's all starting to make sense..."

Upgrade a qc project from a prior version of qc.

Show the current version of qc.

The following commands are grouped under qc corpus.

List all files in the corpus.

Import files into the corpus, copying source files into corpus, formatting them (see options), and registering them in the database. Individual files can be imported, or directories can be recursively imported using --recursive (-r).

$ qc corpus import transcripts --recursive

If you want to import files into a specific subdirectory within the corpus, use --corpus-root (-c). For example, if you wanted to import an additional transcript after importing the transcripts directory, you could run:

$ qc corpus import follow_up.txt --corpus-root transcripts

Several importers are available to format files, and can be specified using --importer (-i). The default importer, pandoc, uses Pandoc to convert files into plain-text, and then hard-wrap them at 80 characters. verbatim imports text files without making any changes. Future importers will include text extraction from PDFs and automatic transcription of audio files.

Move a document from one corpus path to another (or recursively move a directory with --recursive (-r)). Do not move corpus files directly or they will become out of sync with their metadata in the database.

Remove a document from the corpus, along with codes applied to the document. Or recursively remove all documents in a directory with --recursive (-r).

The following commands are grouped under qc code.

Lists all the codes currently in the codebook.

$ qc list --expanded

Goes through all the code files and replaces one or more codes with another. Removes the old codes from the codebook.

$ qc rename humorous funy funnny funny

Displays all occurences of the provided code(s).

$ qc find math science art

Displays frequency of usage for each code. Note that counts include all usages of children. List code names to show only certain codes. In addition to the common options below, code results can be filtered with --max, and --min.

$qc stats --recursive-codes --depth 2

Displays a cross-tabulation of code co-occurrence within the unit of analysis, as counts or as probabilities (--probs, -0). Optionally use a compact (--compact, -z) output format to display more columns. In the future, this may also include odds ratios.

$qc crosstab planning implementation evaluation --recursive-codes --depth 1 --probs

Every qc command supports --settings (-s), which allows you to specify a settings file. This makes it possible to run qc commands from outside the project directory or from within scripts without ambiguity.

The settings file can also be specified via the QC_SETTINGS environment variable. This is makes it easy to check multiple settings files into version control (e.g. for users with different preferences, or to try out different codebook structures).

• --pattern pattern (-p): Only include corpus files and their codes which match (glob-style) pattern.
• --filenames filepath (-f): Only include corpus files listed in filepath (one per line).

• code [codes]: Many commands have an optional positional argument in which you may list codes to consider. If none are given, the root node in the tree of codes is assumed.
• --coder coder (-c): Only include codes entered by coder (if you use different names for different rounds of coding, you can also use this to filter by round of coding).
• --recursive-codes (-r): Include children of selected codes.
• --depth depth (-d): Limit the recursive depth of codes to select.
• --unit unit (-n): Unit of analysis for reporting. Currently "line", "paragraph", and "document" are supported. Paragraphs are delimted by blank lines.
• --recursive-counts (-a): When counting codes, also count instances of codes' children. In contrast to --recursive-codes, which controls which codes will be reported, this option controls how the counting is done.

• --format format (-m): Formatting style for output table. Supported values include "html", "latex", "github", and many more.
• --expanded (-e): Show names of codes in expanded form (e.g. "coding_process:grounded")
• --outfile outfile (-o): Save tabular results to a csv file instead of displaying.