The document discusses the relationship between lighting and worker productivity. It summarizes several studies that show lighting quality is important to workers and can impact satisfaction, motivation and intent to turnover. A landmark study by the Light Right Consortium found that direct/indirect fixtures with wall washing and personal dimming controls led to higher satisfaction and sustained motivation compared to other lighting types. Personal dimming control in particular improved performance on attention tasks and ratings of lighting quality, satisfaction and self-reported productivity. While more evidence is still needed, the study provides scientific evidence that lighting quality can positively impact workers.

1. Lighting is a productivity
tool.
Consider productivity as the proverbial "widgets per hour." Workers
need varying amounts of light depending on what type of work they're
doing and how old they are. When there is enough light, the lighting is
supporting them being able to perform tasks efficiently and accurately.
When there is insufficient light, the opposite happens, which affects
productivity. If the construction team did its job right, sufficient light is
being provided in your building (although it is always a good idea to
survey occupants about what they think of the lighting and make
improvements to ensure they have enough light to do their jobs and are
not being affected by glare). The only thing you have to worry about is
maintenance, making sure the lights are working properly and are
quickly replaced upon failure.
The problem is that productivity is not just widgets per hour. In the
modern office in a service industry, the productivity picture includes a
range of metrics. Worker satisfaction and motivation, for example, are
important metrics - much more so now than they were years ago.
Consider a study in the Journal of Occupational Health Psychology,
which reported that job satisfaction accounted for 63 percent of variance
in organization commitment, which accounted for 80-percent variance
in intent to turnover. In that study, job satisfaction incorporated
satisfaction with the physical environment. A 1987 study in the Journal
of Applied Psychology reported that workplace characteristicsaccounted
for a 31-percent variance in work satisfaction.
Can lighting be used to increase worker satisfaction and motivation and
thereby increase productivity? Experts say yes, but now we are going
beyond the engineering side of lighting - putting footcandles on a work
surface-where everything boils down to math. We must instead look at
how the light is distributed, and where it ends up. It gets trickier here-
proving the benefit, and demonstrating the right way to light a space. But
with the possible benefits being so strong, building owners and managers

2. are wise to investigate their options and take the issue seriously. The
lights in a modern office may be out of the way, but we use them to see
everything-from the marble floor in the lobby to the carpet to the tasks
we perform. How a space is lighted shapes our perception of everything
we see.
The important thing to remember is that occupants want good lighting
and consider it to be very important. Consider the results of several
studies:
 An American Society of Interior Designers (ASID) study determined that68 percent of
employees complain about the light in their offices.
 The 1989 Steelcase Office Environment Index (Louis Harris) showed that workers consider eye
strain to be the leading hazard to their health in the office.
 A Silicon Valley study found that79 percent ofcomputerusers would like better lighting.
In this article,we will talk about the relationship between lighting and productivity,and then unveil the
results ofa new study that indicates a causal relationship between certain types oflighting and higher
worker motivation and satisfaction. Finally, afterlong research by the lighting industry, there is growing
evidence that not only is lighting important,but how a space is lighted can affect how satisfied workersare
with their workplace.
Facing T he Barriers
While building owners and managers may be interestedin better lighting, they may not actually choose to
install it unless they believe that it can be measurably beneficial for their workforce. The three
(interrelated) barriers to adoption ofquality lighting are initial cost, a lack ofscientific evidence ofthe link
between lighting quality and human performance, and the ability to predictfinancial benefits ofincreases
in occupant satisfaction.
Over the years,you have probably heard some ofthe anecdotal evidence:
 Lockheed saved$500,000 per year in energy costs during a lighting upgrade in an engineering
and development facility. The upgrade, however,also resulted in a 15 percent inc rease in

3. productivity and a 15 percent decreasein absenteeism, as reported in Solar Today, May/June
1995.
 West Bend Mutual Insurancereduced energy costs by 40 percentwith a lighting upgrade,
while increasing productivity in the claims processing department by 16 percent, as reported by
the National Lighting Bureau.
 Wal-Mart's Eco-Mart store saw sales become"significantly higher"on the half of the store
lighted by skylights versus the halflighted by electric lighting,as reported in The Wall Street
Journal, November 20,1995.
 In 1986, the main U.S. post office in Reno, Nevada was upgraded, with a causal relationship
demonstratedto subsequent productivity gains by mail sorters and operates ofmechanized
sorting machines, according to the Rocky Mountain Institute.Mail sorters became the most
productivein the western region ofthe United States (from Colorado to Hawaii), while
operators ofthe post office's mechanized sorting machines gained the lowest error rate. While
the energy and maintenance savings amounted to about $50,000 per year, the productivity
gains were anticipated to generate between $400,000 and $500,000 per year.
Compelling, but not scientific enough for some decision-makers. They wanted the "missing link"-scientific
evidence demonstrating a causal link between lighting quality and worker performance.
The lighting industry respondedto this need by forming the Light Right Consortium in partnership with
the U.S. Department ofEnergy, which just completed a landmark study ofthe causal link between worker
performance and lighting.First they conductedmarket research and found:
 7 5 percent ofdecision-makers said that iffactual evidencewere available indicating a positive
effect by lighting on workerproductivity, it would influence what lighting systems they would
buy.
 87 percent ofdecision-makers reported flexibility in lighting budgets ifa return on investment
could be demonstrated.

4.  Respondents reported employee/occupant satisfaction to be even more important than worker
output, retention and absenteeism,which gave the Consortium indications on where to focus
their efforts.
 The owner does not considerlighting quality to be very important, particularly in tenant -
occupied buildings.
 The building manager considers lighting quality to be very important.
Proving the Link: Light Right Consortium Study
The Light Right Consortium next set up a research study to address the question, "Can different forms of
realistic officelighting affect the performanceofoffice work or the well-being ofemployees?"The primary
variables to be studied included room surface brightness and personal control. It was set up as a field
simulation, conductedin the field but with simulated tasks and a high degree ofexperimental control that
is typical oflaboratory studies-this approach being taken to maximize realism and validity ofthe results.
In an office in Albany, NY, temporary workers were studied performing a range ofoffice tasks under six
lighting conditions. Based on the study's findings, these conclusions can be drawn:
 Direct/indirect fixtures with perimeter wall washing is considered more "comfortable"and less
"uncomfortably bright"than lensed and parabolic troffers,
 About 70 percent ofoccupantsconsidered lensedand parabolic to be "comfortable "overall
versus 81-85 percent for direct/indirectwith wall washers and 91 percent for the personal
dimming control condition.A higher percentage ofthe population prefers light on the ceiling
and walls.
 People with personal dimming control showed more sustained motivation and improved
performance on a measureofattention. They also reported higher ratings oflighting quality,
overall environmental satisfaction and self-rated productivity.
 People who are more satisfied with their lighting rate the space as more attractive, are happier,
and are more comfortable and satisfiedwith their environment and theirwork.
 Lighting and task conditions that improvevisibility lead to better task performance.
While putting light on ceilings and walls was found to be an important factor, personal dimming control
emerged as the biggest star ofthe study. Occupants were allowed to dim the direct component ofthe
direct/indirect fixture over theirworkstations using theirPC. This not only made the workers more

5. satisfied, but also resulted in increased motivation throughout the day-a primary productivity metric. In
addition, personal dimming control results in cumulative energy savings thatcan be significant.
. The next challengefor the Light Right Consortium is to run a field study where thesequestions are
investigated in an actual workplace and organizational productivity metricscan be collected.
After the full field study, which is anticipated to begin in 2004, the next step for the Light Right
Consortium is to develop tools-such as lighting analysis software thatintegrates potential productivity
benefits with energy savings to create a life-cyclecostanalysis for various lighting approaches being
considered for projects

6. Natural daylight is so far merged with architecture that is accepted
a p r i o r i
as integral to it. Architecture is
s h a p e d
around pre-existingdaylight. Artificial light, a man-made effect, needs far
more justification and rationalization of the design decision-making, as itcomes
a f t e r ,
to illuminate a pre-existing space and tries tointerpret it. In other words,
architecture is creating space aroundnatural light, while artificial lighting design is
creating light aroundpre-existing space.In the vast majority of artificial lighting
projects the lightingdesigners are called in to provide a lighting scheme that
recognisesthe pre-existing architecture, acknowledges the restrictions that itposes
and reveals its meanings. In the quest for solutions thedesigners follow principles,
which they consider prerequisites of good design. Some of them are intuitive and
some are far soclearly functional that they are no longer distinguished as
principlesbut as criteria of good design. The latter, mainly derive from theresults of
the research undertaken in the quantitative field: glare,illumination levels, spectral
qualities and colour temperature forexample. The former, succumb to
the objectivity of quality: culturaldifferences, personal taste, aesthetic education,
personal orcollective memories, geographical and climatic differences as wellas the
digestion of emerging technologies which creates anuncertainty and unease when
trying to evaluate them.William Lam identified the contradiction of laboratory
results andreal world perception of lighting quality quiet early (1940’s). Heprotested
against a one-dimensional view that did not make sensewhen strictly applied:
“There is a great need for new ways of conceptualising and specifying performance
criteria for theluminous environment which go far beyond codes based on
tasklighting conditions alone” (1). He then tried to answer the aestheticquestion
himself by turning to perception and, the widely spreadinginfluence at that time, of
the gestalt school. So in a way, despitelocating the problem he implemented
science of a different field totry and answer it.The
a e s t h e t ic is s u e
is beyond doubt a philosophical one and itdeviates far from the purposes of real-
world design to try andanswer it. It is worth considering that architecture, having
both apractical nature and an aesthetic one, is destined to similaraesthetic
questions, which have fuelled the long history of architectural theory and critics.
Those questions have never beenmore condensly expressed in architecture other,
than with theanalysis of the form-function dipole and its dominance upon
others.Different movements in architecture have evaluated therelationship between
form and function and even their definition ona different basis. In some periods
form and ornamentations werethe main issue and aim of exploration in
architecture, while in thepost-industrial era the function gained such a meaning that
it
consumed within it the importance of form. Associating this withlighting, if the well
‘functioning’ of lighting schemes depends on itsnumerical performance, then the
‘form’ issue corresponds to how
f o r m
i

7. has been interpreted and lit in different eras and culturalinfluences. But then again,
is function purely objective andquantifiable and form purely subjective and
abstract?Unfortunately, lighting design does not have the historicalbackground of
architecture to try and originate theoretical material,since it starts having a serious
presence from the 1920s andonwards with the
a r c h a ic
period being at the end of the 19
th
century. However, this small historic period has been comprised bya plethora of
changes and movements; some of them distinctlyindividual and self-contained and
some others very closely related,overlapping, almost as branches deriving from the
same trunk, andsometimes contradictory(2). For example purism,
brutalism,cubism, constructivism and Bauhaus are all representing valuesthat
modernism can claim for as well. Happening in almost thesame period they have
influenced each other and all together fromthe vast changes of the pre-war and
the interwar era.Additionally, the technological inventions of light lamps during
the20
th
century were succeeding one another within decades anddominated the markets in
half that time. The perfectionism of theincandescent sources was followed by the
invention of thefluorescent lamps and this resulted in the opening towardsproducing
light other than with burning a material. As a resultlighting design was forced to go
through many changes andincorporate those changes of tools as well as to respond
to the newneeds of design trends.One problematic element of modern design for
example were thefull glazed facades of modern houses which had as intention
toframe the exterior view and capture it, while establishing a literaland
phenomenal transparency. And this was the case in daytime.This had as a result
though, that when the interiors were lit bynight, landscape was invisible and the
glass panes were behavinglike mirrors. The users no longer had the opportunity to
perceivethis continuity but witnessed a case of limited privacy. The interiorno
longer was the point of observation but a visual focus of thesurrounding landscape
and the users themselves were the objects.No longer viewers but the viewing
theme itself.The fascinating changes in the built history of the 20
th
century givea small but interesting material to research and identify if there
aredistinct movements in lighting design, as there are in architectureand arts,
which directed the collective sense of qualitative design.The first step to take is to
identify what a school, style ormovement is having as basic characteristics that
discern it from theothers.
i
Form here has the meaning of how light visualizes a built form, astructure and
therefore renders it visible