### Task related columns
- questionName : Minor task type for differentiate two types of Comparing Values task.
"value_q1" = Reading Value task
"aggregate_avg_q1" = Comparing Averages task
"aggregate_q1" = Finding Maximum task
"compareValue_q1_across" = Comparing Value task with sampling two from different two categories
"compareValue_q1_within" = Comparing Value task with sampling two from the same category
- taskGroup : Major task type
"readValue" = Reading Value task
"compareValue" = Comparing Values task
"findExtremum" = Finding Maximum task
"compareAggregatedValue" = Comparing Averages task
- question
- options0
- options1
- correctOption
- userChoice
- questionDifficulty
- questionTurn : the turn of the question
- isCorrect
- startTime
- endTime
- completionTime
- stimuliTurn : the turn of the spec
- specID : (see stimuli/specs.json)
- userAgent : WebBrowser info

### Data distribution related columns
- assignmentID : A string corresponding to a data distriution.
{cardinality}_{#/category}/{Entropy_Q1}{Entropy_Q2}{Entropy_N}_{Clusteredness}__{Correlation}
For example, "3_30/HHH_H__W" means the data distribution having 3 cardinalities, 30 records per category, high Q1 entropy, high Q2 entropy, high N entropy, high clusteredness, and weak correlation.
- dataset : a corresponding data set in the "stimuli" folder
- Q1 : the primary quantitative field of the dataset
- Q2 : the secondary quantitative field of the dataset
- N : the categorical field of the dataset
- Q1_entropy
- Q2_entropy
- Nentropy : Entropy of N
- correlation : Pearson correlation between Q1 and Q2
- cluster : the sum of z-distances of each category
- cardinality
- nPerCategory
- clusteredness_class
- correlation_class
- Q1_entropy_class
- Q2_entropy_class
- N_entropy_class
- stratum

### Visualization related columns
- channel : the visual encoding that maps Q1, Q2, N to first, second, and third channels respectively in "channel".
For example, "x y color" means Q1:x, Q2:y, N:color.
- Q1_channel : the channel encoding Q1
- Q2_channel : the channel encoding Q2
- name_channel : the channel encoding N (name).
- containerHeight : the height of the div element containing the visualization
- containerWidth  : the width of the div element containing the visualization
- height : the height of the visualization
- width  : the width of the visualization
- windowInnerHeight : Javascript window.innerHeight value
- windowInnerWidth  : Javascript window.innerWidth value
- windowOuterHeight : Javascript window.outerHeight value
- windowOuterWidth  : Javascript window.outerWidth value

#### Javscript `window.screen` object's properties
- windowScreenAvailHeight
- windowScreenAvailLeft
- windowScreenAvailTop
- windowScreenAvailWidth
- windowScreenColorDepth
- windowScreenHeight
- windowScreenPixelDepth
- windowScreenWidth

### Participant info
- userID
- gender
- education
- age
- vision_deficiency
- vision_impairment_description