A study looking at data judgement accuracy in pie and donut charts
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Pie and Donut Chart Evaluation

This project was used in a study that used the Mechanical Turk platform to test a series of pie chart variations.

The study is built on the excellent Experimentr.js project.


The collected data files are in the analysis/results directory.

Data Files

  • reshaped-unique.csv: trial data in CSV format, with incomplete trials removed
  • demographics.csv: demographics data in CSV format
  • merged-data.csv: trial data with demographics data included on every row.
Field Name Description
time_start_time-trial Unix time for beginning of the question
time_end_time-trial Unix time for ending of the question (if this is missing, it is the same as time_end_trials from the demographics data)
rotation randomly selected rotation value showing the chart's rotation
log_error Log absolute error as reported in the paper
totalSequence Position within the entire study for that participant
arc_angle_area answer to multiple choice question asking participant whether they preferred using arc-length, angle, or area in their judgements
judged_true Judged answer minus true answer
ans_percentage_diff (given-correct)/correct
opposite_ans 100 - correct_ans
chart_type Pie, Donut, Arc-Length, Area, Pie Angle, Pie Donut
ans_trial Given answer
postID ID generated by experimentr
time_diff_time Time in miliseconds that it took to answer the question
correct_ans Correct answer

Running The Study

To run the project, you'll need Redis and Node.js.

To start the Redis server, run the following command from the project directory:

redis-server redis.conf

The Node server works on port 80, so it needs root access, and the project is set to use Forever.js to ensure it keeps running:

forever start app.js

Once you have the project running, you can visit localhost in your browser to see the survey.