Taking Email to Task: The Design and Evaluation of a Task
Management Centered Email Tool
Victoria Bellotti, Nicolas Ducheneaut, Mark Howard, Ian Smith
Palo Alto Research Center
3333 Coyote Hill Road
Palo Alto CA94304, USA
+1 650 812 4000
{bellotti, nicolas, mahoward, iansmith}@parc.com
ABSTRACT
Email has come to play a central role in task management,
yet email tool features have remained relatively static in
recent years, lagging behind users’ evolving practices. The
Taskmaster system narrows this gap by recasting email as
task management and embedding task-centric resources
directly in the client. In this paper, we describe the field
research that inspired Taskmaster and the principles behind
its design. We then describe how user studies conducted
with “live” email data over a two-week period revealed the
value of a task-centric approach to email system design and
its potential benefits for overloaded users.
Keywords
Email, task management, user studies, system evaluation
INTRODUCTION
An increasing body of literature points to the importance of
email as a task management resource. Mackay [15] detailed
how it supports a variety of time and task management
activities. Whittaker and Sidner [22] extended her findings
to show how the email inbox is a repository of “to-dos”,
“to-reads” items of “indeterminate status” and “ongoing
correspondence” that can be difficult to deal with. More
recently, we discussed how email is transforming into a
“habitat”, the central place from which work is received,
managed, and delegated in organizations [9].
In spite of the fact that users’ have co-opted this flexible
application as a critical task management resource, the
fundamental messaging metaphor of most clients is not
optimized for task management. Email users clearly feel
overwhelmed and daunted by the time it takes to deal with
all the work coming in through this medium [14, 22].
Acknowledging this problem, a few recent projects have
tried to overhaul email’s interface. Several have diminished
the user’s cognitive burden by automating aspects of the
filing and organizing of the myriad incoming messages [6,
17, 20]. But this only addresses the problem of managing
the volume of email. Others have explored different
avenues. Among these, CAFE [21] is probably the most
ambitious. Based on studies of email users’ behavior,
CAFE offers three modes (busy, cool and curious) to
satisfy varying needs in different situations. Cadiz et al.’s
prototype [7] focuses on keeping up with the flow of
messages as they arrive and the activity of email triage on a
body of new messages. In a similar vein Rohall et al. [19]
describe visualization techniques to quickly identify
dependencies between messages in a conversation. Finally,
Gwidzka’s work [13] focuses on the management of
pending tasks and the process of reminding to act on them.
This body of research is, however, only in its infancy, with
each prototype only addressing one facet of the problem of
task management in email. The situation is similar with
commercial software touting personal information
management (PIM) features, such as Microsoft Outlook,
which aggregate without integrating diverse components of
task management. The task list in Outlook is, for instance,
disconnected from the inbox, even though messages and to-
dos are often indistinguishable [9, 22]. Outgoing messages,
frequently conveying important task-related information
(such as outstanding actions for others) are hidden, out of
context, in the outbox. And time sensitive information
relating to message content is restricted to the calendar.
Based on our studies of email use, we built Taskmaster, an
email system entirely redesigned for task and project
management. Taskmaster offers a new solution to the
often-decried “pain of email” [8] by recognizing upfront
that this technology is not simply concerned with
messaging, but that dealing with email and managing tasks
and projects are indistinguishable [15, 22]. We accomplish
this goal purely through a redesign of email’s user
experience without changing its fundamental technical
infrastructure.
In this paper we first summarize our investigations
regarding task management in email. Based on these
studies, we identify the major facets of email task
management that require support. We then describe our
implementation of such a system. Finally, we present the
results of an extended evaluation, during which nine users
managed their email with our prototype.
STUDIES OF TASK MANAGEMENT IN EMAIL
Based on our previous work [9, 10], and that of others cited
above, we hypothesized that much of email’s complexity
(and overload) depends on the nature of the task
management activities it is used to support. So we devised
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CHI 2003, April 5–10, 2003, Ft. Lauderdale, Florida, USA.
Copyright 2003 ACM 1-58113-630-7/03/0004…$5.00.
Ft. Lauderdale, Florida, USA • April 5-10, 2003 Paper: Integrating Tools and Tasks


Volume No. 5, Issue No. 1 345

a multi-phase study of Outlook™ and Eudora™ users to
understand this better. We recruited 11 people, though not
all could agree to all the phases (and subsequent prototype
tool use; see table 1.). The phases were as follows:
Phase 1. For 7 participants, we installed standard filters to
save copies of all incoming and outgoing email to a special
folder. Participants were allowed to delete private messages
from the folder (they reported deleting about 10% of the
messages). Two to three weeks worth of data in the middle
of the time period in which the filters were installed was
analyzed by hand, message-by-message to see who was
being emailed about what and how messages related to
each other, in order to determine how tasks and
collaboration took place in email. So we focused on the
following:
• Addressing: Whether each message was individual,
multiple or list addressed, implying its likely import in
terms of thread tracking (as argued in [2]).
• Threads: Series of topically related messages and
replies (unlike [22] we analyzed content as well as
subject lines and thus found a greater average density of
threaded messages; 46.9%). Threads on distribution lists
were only included if the participant contributed to them.
Phase 2. We video recorded 20 to 60 minutes of email
‘triage’ (this is the practice of handling incoming email and
related to-dos and organization [7]). We arranged to be in
the participant’s office at a normal time for this activity to
occur. If it lasted less than 20 minutes, we returned for a
second session. Participants were asked to describe what
they were doing, but to try to work as normal.
Phase 3. These observations were shortly followed by
interviews, covering the participant’s role and use of email.
We asked open-ended questions (e.g., “what is your biggest
organizational headache in email?”) and also used 5-point
Likert scales to get participants to rate how much they did
certain things or used certain features of their email client.
Phase 4. At the end of our filtered data collection period,
we conducted follow-up interviews to complement and
verify our analysis for accuracy of interpretation of the
filtered message activity (we were close to 100% accurate).
FINDINGS: TASK MANAGEMENT IN EMAILManaging Tasks in Email: Quantity and To-Dos
Our results from phases 1-4 (see [5] for details) focusing on
task activity in email, show that some tasks require only a
simple rapid response taking just a few seconds (similar to
the one-touch model described in [22]). In other cases, a
response might be interrupted or delayed (for minutes,
hours, even days) while one takes time to gather
information (e.g. from the Web, or documents) to complete
the task – we call these extended-response tasks. Here, it is
the volume of email and to-dos for oneself that cause
trouble to email users, not its structure.Managing Tasks in Email: Complexity and Others’ To-Dos
A significant number of tasks in email are more complex
rapid- or extended-response tasks. These are
interdependent tasks; tasks with obligations that also
depend upon the to-dos of others. These are characterized
by complex threads of email (and other communication
such as phone calls) and are often associated with delays of
anything from a few hours to weeks, waiting for responses
that enable progress.
Role Study Phase Tool Use
Attorney (A) - 2 3 - -
Legal Secretary (LS) - 2 3 - -
Business Developm’t (BD1) - 2 3 - 2 days
Public Relations (PR) 1 2 3 4 1 week
Group Manager 1 (GM1) 1 2 3 4 -
Group Manager 2 (GM2) 1 2 3 4 -
Group Manager 3 (GM3) - 2 3 - >4 months
Patent Process Mgr (PPM) 1 2 3 4 -
Researcher 1 (R1) 1 2 3 4 1 day
Researcher 2 (R2) 1 2 3 4 2 weeks
Researcher 3 (R3) 1 2 3 4 >4 months
Researcher 4 (R4) - - - - >4 months
Researcher 5 (R5) - - - - 2 weeks
Business Developm’t (BD2) - - - - 1 week
Table 1. Roles and participation in study phases and
prototype use. Due to the heavy commitments required,
most participants took part in a subset of the phases.
The factors that seem to relate most to a sense of overload
are the number of threads one is tracking per day, and the
length of the intervals between messages in those threads.
Multiplying these two factors for each participant gave us a
simple metric that corresponded more closely than the
number of messages per day with reports of overload. The
explanation is simple: if one is keeping track of a thread
with large intervals between messages, the last message
reminding one about that thread drifts out of sight in the
inbox as more email arrives. The more one gets involved in
threads like this, the harder it is to keep track of them. This
leads to significant amounts of time invested in ‘managing’
task-related content. From analysis of video recordings, we
found that our participants spent about 10% of their email
work time filing messages they thought they might need for
future work (cf [1]) and about 8% scrolling around and
inspecting folders to find messages associated with active
threads. This problem is compounded by the fact that
attachments and links often accompany these messages,
and must also be acted upon (by skimming, or reading and
then storing somewhere memorable) before any further
progress can be made. Most importantly perhaps, these
numbers do not factor in the time and organizational
resources lost when a to-do has drifted out of sight and has
not been acted upon, as well as the deep frustration
experienced by email users when this situation presents
itself [22].
We identified seven specific problems that participants in
our study experience with task management in email:
1. Keeping track of lots of concurrent actions: One’s own
to-dos and to-dos one expects from others.
2. Marking things as important or outstanding amongst
the less important items.
Paper: Integrating Tools and Tasks CHI 2003: NEW HORIZONS


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