  Data is everywhere but may not be accessible to everyone. Conventional data
visualization tools and guidelines often do not actively consider the specific
needs and abilities of people with Intellectual and Developmental Disabilities
(IDD), leaving them excluded from data-driven activities and vulnerable to
ethical issues. To understand the needs and challenges people with IDD have
with data, we conducted 15 semi-structured interviews with individuals with IDD
and their caregivers. Our algorithmic interview approach situated data in the
lived experiences of people with IDD to uncover otherwise hidden data
encounters in their everyday life. Drawing on findings and observations, we
characterize how they conceptualize data, when and where they use data, and
what barriers exist when they interact with data. We use our results as a lens
to reimagine the role of visualization in data accessibility and establish a
critical near-term research agenda for cognitively accessible visualization.
