The State of the States in Intellectual and Developmental Disabilities*
Accessible Data Visualization
OVERVIEW
This is a joint work between the Coleman Institute for Cognitive Disabilities and the CU VisuaLab to make financial data accessible to people with IDDs, in the hope of supporting their self-advocacy and self-determination. Drawing on the literature, we identified three design elements: Chart Type, Chart Embellishment, Data Continuity. We conducted a mixed-method web-based experiment with 12 participants with diagnosed IDDs (and 22 without IDDs) to investigate each of these elements in terms of Task Completion Time & Accuracy; Subjective Preference. Our results suggest 5 design guidelines to make bugetary data cognitively accessible:
(1) Avoid pie charts
(2) Use familiar metaphors
(3) Manage visual complexity
(4) Use discrete encodings for axis-aligned representations
The experiment and collected data could be accessed at Accessible Visualization. Below we will illustrate these guidelines with examples from our design in 3 case studies using the State of the States datasets.
CASE STUDY 1: US TOTAL FISCAL EFFORT FROM 1997 - 2017
US Total Fiscal Effort For Community/Family Services And Institutional Services From 1997 - 2017
Use discrete encodings for axis-aligned representations: Scatter plots made it easier to identify the overall trend of change in data.
US Total Fiscal Effort For All Services From 1997 - 2017
Manage visual complexity: Thickend line charts with dollar signs expedited the process of finding the maxium value without overwhelming participants.
CASE STUDY 2: US TOTAL IDD SPENDING FROM 1997 - 2017
US Total IDD Spending From 1997 - 2017 (Federal, State, Local Combined)
Use discrete encodings for axis-aligned representations: Countable Isotype visualizations improved task performance and boosted confidence in accuracy.
US IDD Federal Spending from 1997 - 2017
Manage visual complexity and use familiar metaphors: Extraneous image impeded data interpretation, however stretched icon bars signified the context and improved performance.
CASE STUDY 3: INDIVIDUAL STATES FISCAL EFFORTS IN 2017
US Total Fiscal Effort Across The States From 1997 - 2017 (Rocky Mountain Area)
Avoid pie charts: Though usually used by default, pie charts were not as good as stacked bar charts for size comparison.
US Total Fiscal Effort Across The States From 1997 - 2017 (Rocky Mountain Area)
Manage visual complexity: Waffle charts may overencourage counting and slow down data analysis.
