  Feedback tools help people to monitor information about themselves to improve
their health, sustainability practices, or personal well-being. Yet reasoning
about personal data (e.g., pedometer counts, blood pressure readings, or home
electricity consumption) to gain a deep understanding of your current practices
and how to change can be challenging with the data alone. We integrate
quantitative feedback data within a personal digital calendar; this approach
aims to make the feedback data readily accessible and more comprehensible. We
report on an eight-week field study of an on-calendar visualization tool.
Results showed that a personal calendar can provide rich context for people to
reason about their feedback data. The on-calendar visualization enabled people
to quickly identify and reason about regular patterns and anomalies. Based on
our results, we also derived a model of the behavior feedback process that
extends existing technology adoption models. With that, we reflected on
potential barriers for the ongoing use of feedback tools.
