UC Berkeley
Indoor Environmental Quality (IEQ)
Title
Listening to the occupants: a web-based indoor environmental quality survey
Permalink
https://escholarship.org/uc/item/8cf6c6dr
Authors
Zagreus, L.
Huizenga, C.
Arens, E.
et al.
Publication Date
2004-12-01
Peer reviewed
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University of California
Listening to the occupants: a Web-based indoor environmental
quality survey
Introduction
Comprised of faculty and researchers at the University
of California, and supported by the National Science
Foundation and public- and private-sector industry
partners, the Center for the Built Environment (CBE)
at the University of California, Berkeley works to
inform the building industry about new building
technologies and design techniques. A core tenet of
CBE is that everyone in the building process benefits
from learning how a building actually performs in
practice.
Historically, building occupants have been underuti-
lized as a source of information on building perform-
ance. Prior to Web-based surveys, creating,
distributing, and analyzing paper questionnaires was
a time-consuming and expensive process, and diagnos-
tic paper surveys necessarily took a long time for
occupants to complete. In addition, surveys have
tended to be project-specific and not often repeated.
One exception is the Probe study in which a standard-
ized survey was used to benchmark building perform-
ance (Leaman et al., 1997) for a large number of
energy-efficient buildings. CBE has developed a Web-
based survey (see http://www.cbesurvey.org for a
demonstration version of the CBE occupant IEQ
survey) that is similarly standardized and focused on
indoor environmental quality (IEQ), but by being
Web-based, it offers two additional benefits. First, it
can be inexpensively administered to many buildings.
Second, its interactive branching questions allow it to
‘‘drill down’’ into areas that the occupants rate poorly,
Abstract Building occupants are a rich source of infor mation about indoor
environmental quality and its effect on comfort and productivity. The Center for
the Built Environment has developed a Web-based survey and accompanying
online reporting tools to quickly and inexpensively gather, process and present
this information. The core questions assess occupant satisfaction with the foll-
owing IEQ areas: office layout, office furnishings, thermal comfort, indoor air
quality, lighting, acoustics, and building cleanliness and maintenance. The sur-
vey can be used to assess the performance of a building, identify areas needing
improvement, and provide useful feedback to designers and operators about
specific aspects of building design features and operating strategies. The survey
has been extensively tested and refined and has been conducted in more than 70
buildings, creating a rapidly growing database of standardized survey data that
is used for benchmarking. We present three case studi es that demonstrate dif-
ferent applications of the survey: a pre/post analysis of occupants moving to a
new building, a survey used in conjunction with physical measurements to
determine how environmental factors affect occupants’ perceived comfort and
productivity levels, and a benchmarking example of using the survey to establish
how new buildings are meeting a client’s design objectives.
Leah Zagreus, Charlie Huizenga,
Edward Arens and David Lehrer
Center for the Built Environment, Berkeley, CA, USA
Key words: Benchmarking building quality; Indoor
environmental quality; Occupant satisfaction; Online
reporting, Post-occupancy evaluation (POE); Web-based
surveys
Leah Zagreus
Center for the Built Environment, 390 Wurster Hall
#1839, Berkeley, CA 94720-1839, USA
Tel.: +1 510 642 6574
Fax: +1 510 643 5571
e-mail: lzagreus@alumni.sims.berkeley.edu
Practical implications
In addition to its use in benchmarking a building’s performance against other buildings, the CBE survey can be used
as a diagnostic tool to identify specific problems and their sources. Whenever a respondent indicates dissatisfaction
with an aspect of building performance, a branching page follows with more detailed questions about the nature of the
problem. This systematically collected information provides a good resource for solving indoor environmental
problems in the building. By repeating the survey after a problem has been corrected it is also possible to assess the
effectiveness of the solution.
Indoor Air 2004; 14 (Suppl 8): 65–74
www.blackwellpublishing.com/ina
Printed in Denmark. All rights reserved
Copyright Blackwell Munksgaard 2004
INDOOR AIR
65
and thus in many cases diagnose the root of the
problems. A set of core questions is used to assess
occupant satisfaction and comfort with IEQ issues
including indoor air quality, thermal comfort, lighting
and acoustics. The branching questions arise only if the
occupant indicates dissatisfaction with a given issue, so
that the survey does not burden the occupant with
detailed questions unless problem areas are detected.
The survey supports optional modules to address
special issues not covered in the core questions, and
can be offered in multiple languages.
The survey can be applied widely to evaluate the
performance of individual buildings as well as to
systematically compare the performance of groups of
buildings. Case studies presented below indicate that
information provided by the survey can positively
influence indoor environmental quality for occupants
of existing as well as future buildings. Useful feedback
is provided to operations staff, supporting operational
adjustments that can lead to improved IEQ in a
relatively short timeframe for occupants of existing
buildings. Survey results also inform the design com-
munity about the effectiveness of specific technologies
and strategies. In addition, the survey is proving a
useful resource for facility managers and building
owners involved in acquiring, operating and improving
their building portfolio.
Methods
Survey development
The survey is comprised of a core survey and optional
survey modules. Each organization using the survey
has the option of employing the core survey or
customizing the survey to include additional modules
that support specific information needs. The core
survey includes modules for office layout, office
furnishings, thermal comfort, air quality, lighting,
acoustics, and building cleanliness and maintenance.
Examples of optional modules include wayfinding,
safety and security, operable windows, shading sys-
tems, floor diffusers, and washrooms. Core questions
stay consistent from survey to survey to maintain data
integrity for the purposes of benchmarking and trend
analysis.
The survey has been extensively tested and refined,
and facility managers and designers have evaluated the
reporting format to determine the utility of various
report designs. An established testing method called
‘‘cognitive interviewing’’ was used by the Survey
Research Center at UC Berkeley to assess how well
respondents were able to comprehend and accurately
report answers to survey questions (Eisenhower, 2000).
Cognitive interviews allow researchers to examine the
thought processes that affect the quality of answers
provided to survey questions. The primary technique
used was the ‘‘concurrent think aloud’’ method where-
by each respondent was asked to comment out loud
about anything crossing his or her mind while reading,
interpreting and answering each question. This tech-
nique was supplemented by paraphrasing (asking the
respondents to put something in their own words) and
systematic probing. Seven people participated in this
testing. In addition, occupants who took surveys in the
initial buildings were asked to rate the survey. Results
were used to refine the survey organization, question
text, graphic design of the scales, and the process
required to access the survey website.
The time required to complete the survey has been
monitored, and occupants have also evaluated the
length of each section of the survey. The approximate
time required to complete the core survey is 5–12 min;
time to completion varies depending on the number of
branching questions and comments answered. This
length of time has not been regarded as an impediment
to completion in most (but not all) of the buildings
surveyed to date. Surveys that include several custom-
ized modules in addition to the core survey have had
completion times of up to 20 min. Organizations that
choose to implement longer surveys are briefed regard-
ing the potential negative effect that longer surveys can
have on response and completion rates.
Customization and continued survey development. As
mentioned above, survey customization is possible,
and clients can add new or existing modules to the core
survey to suit the needs of a particular project or
audience. Indeed, owing to the flexible infrastructure
underlying the survey, whole new survey types have
been developed. One CBE partner has commissioned a
customized occupant IEQ survey, as well as the
creation of two new building quality surveys. The first
of these surveys, an operations and maintenance staff
survey, aims to determine how satisfied the staff is with
the design of the building and its effect on their ability
to run and maintain the facility. Second, a design and
construction process survey, polls the design and
construction teams for their satisfaction with the
process of building the facility. Each of the three
surveys is designed for a distinct population, and
during a post-occupancy evaluation (POE), all three
surveys can be conducted in a building to learn how it
is performing for its occupants, operators, and design
team.
We also have the ability to study survey design itself.
Due to the nature of the Web, and the flexibility of the
survey architecture, we can randomly assign respond-
ents to slight variations on survey instruments. We
have done so in an evaluation of 5-point vs. 7-point
scale sizes (Zagreus and Huizenga, 2003) and are
currently conducting research into the orientation of
the scales (satisfied on the left vs. satisfied on the right).
Similar investigations, such as the effect of question
Zagreus et al.
66
order within and between survey categories, are also
possible.
Multilingual capabilities. We have implemented the
occupant IEQ survey in buildings across the USA
and Canada, and in Europe. The structure of the
survey scripts enables us to offer the survey and
accompanying reporting tools in any language. The
survey can be offered in multiple languages, with
respondents choosing the desired language at the time
they access the survey Web page. The strings for each
language are stored centrally, and depending on the
language in which the survey is being taken, the
appropriate string is retrieved and displayed at survey
run-time. The foreign language questions have been
mapped to the English ones so that comparisons of the
responses from different buildings can be made regard-
less of the language in which the survey was taken. The
survey has already been translated and implemented in
Finnish, and is also available in Danish.
Implementation
The occupant IEQ survey implementation process
typically begins with an e-mail informing building
occupants of the survey Web site address, start date
and end date. This e-mail is drafted and sent either by
CBE or the sponsoring agency. Subjects can access the
survey at their convenience. After linking to the survey
using a Web browser, respondents see a welcome screen
informing them of the purpose of the survey. The
welcome page also advises them of the amount of time
it should take to complete the survey, and their rights
as a research participant. Participation in the survey is
voluntary and anonymous, and respondents may opt
out at any time. Upon starting the survey, participants
click through a series of questions asking them to
evaluate their satisfaction with different aspects of their
work environment (Fig. 1). Satisfaction is rated on a
seven-point scale ranging from ‘‘very satisfied’’ to ‘‘very
dissatisfied’’, with a neutral midpoint. In most cases,
respondents who indicate dissatisfaction (the lowest
three points on the scale) with a particular aspect of
their work environment are ‘‘branched’’ to a follow-up
screen probing them for more information about the
nature of their dissatisfaction (Fig. 2). Respondents
who indicate neutrality or satisfaction (the upper four
points on the scale) move directly to the next survey
topic. Tailoring the survey in this fashion enables
diagnostic information to be gathered about potential
problems in the building, and keeps questions relevant
to each respondent while making the survey as succinct
as possible. When applicable, respondents are also
asked to assess the impact of environmental factors on
their effectiveness in getting their job done.
Basic demographics are collected from respondents,
as well as information about their workspace. Core
survey questions elicit whether the workspace is in the
core or perimeter of the building, near a window, the
orientation (e.g., north), and the type (e.g., private
office). Survey clients are encouraged to include zone
questions with floor plan schematics in order that
Fig. 1 Sample occupant IEQ survey page
A Web-based indoor environmental quality survey
67
occupants can indicate proximity to specific building
systems (zones must be large enough to ensure
respondent confidentiality). Clients may also include
custom questions about work duties so that survey
data can be analyzed in light of job-specific tasks.
Occupant responses are collected and recorded in a
secure SQL Server database (SQL is a standardized
query language for storing, retrieving and modifying
information in a database). A survey typically stays
open for 1–2 weeks. The rate of participation is
monitored; and if it is going slowly, reminder e-mails
may be sent. Of the buildings surveyed to date,
response rates have ranged from 27% to 88%, with
the majority of response rates between 45% and 65%,
and the mean at just over 50%. Overall, we have found
that response rates are higher when the initial message
introducing the survey is sent directly from a person
who is well known and a decision maker within the
participating organization. The introductory e-mail for
the survey with the lowest response rate was poorly
executed; it was forwarded three times before it reached
the occupant, each time with an additional header
attached. By the time it arrived to the intended
recipients, the reader needed to scroll to the bottom
of the message to read the original text. This dimin-
ished the perceived importance of the study and is
likely to have resulted in the low response rate. The
study with the highest response rate was introduced
with an e-mail sent directly from the head of the
organization noting an ‘‘important survey’’ for all
building occupants. While likely leading to the high
response rate, often this type of cooperation and
attention from the head of an organization is difficult
to orchestrate, and this is true of paper surveys as well
(Zimring and Rosenheck, 2001; Leaman, 2003).
For census surveys like ours, the survey research
industry rule of thumb is that a 50% response rate is
required to reduce non-response bias to an acceptable
rate (Hill et al., 1999). Although it is difficult to know
what the non-response bias might be, we have looked
for trends in our data and have found no statistically
significant relationship between response rate and
occupant satisfaction levels.
Reporting results
Individual building report. Data is reported using an
automated Web-based reporting tool, and is quickly
made available to clients after survey implementation,
typically within a week following the survey close date.
Responses of participants who answer less than 15
questions are removed from the final data set. The home
page of the report summarizes the satisfaction ratings for
each of the survey categories. Satisfaction ratings are
tabulated for each point on the scale, and are also
summarized into three bins: satisfied (top three points),
Fig. 2 Sample follow-up page
Zagreus et al.
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