Advancing the effective use of light for society and the environment.

Vol. 2, No. 1

Wednesday, January 22, 2003

Researchers Look for Link Between Lighting and Productivity

Over this past summer and fall, LRC researchers have been running a study that looks for a link between lighting and workplace productivity. This issue has been of interest to the researchers and people in the lighting industry for some time, but proof of such a link has been elusive. Funded by the LightRight Consortium, this new study is the largest to date. The LRC team is working with the National Research Council of Canada's Institute for Research in Construction on the project.

The Institute developed the software and protocols used, while the LRC recruited and supervised the participants, collected the data, and performed the photometry measurements. The Institute is analyzing the data, and they and the LRC will write the final report jointly. The research design, which used temporary workers performing a wide range of office tasks, was also a collaboration between the Institute and the LRC.

Claudia Hunter, a human factors research specialist for the LRC, says, "We hope, once and for all, to link productivity to better lighting in a way that's supported by research data. We want to give people a reason to upgrade their lighting."

The study examines four different lighting conditions with varying degrees of brightness and of user control in an office setting that included a typical arrangement of cubicle workstations.

Dr. Peter Boyce, who, with Dr. Jennifer Veitch and Dr. Guy Newsham of the Institute, created the research design, elaborates: "Condition 1 is a regular array of three-lamp parabolic luminaires, the sort of thing that's common in office buildings today. Condition 2 is a linear array of suspended direct/indirect luminaires with wall washing. This arrangement is called 'best practice' by the industry. Condition 3 is the same as condition 2, but each workstation has a small desk lamp with a switchable compact fluorescent lamp that gives the occupant control of the light level. Condition 4 has a direct/indirect luminaire suspended over the center of each cubicle, and occupants have direct control of the downward lighting using a computer-based dimming system. We're calling conditions 3 and 4 'best practice plus individual control.' Conditions 1 and 2 provide the same illuminance on the desk, while the lighting in conditions 3 and 4 depends on how the occupants use their individual controls." The researchers ran 50 workers for each of the four conditions, plus 50 more workers who experienced both conditions 1 and 4.

Hunter supervised the work of many of the temporary workers who participated in the study. "We had the participants perform a variety of tasks," she says. "There were low-level performance tasks like typing, and then there were other tasks that involved judgment, decision making, and persistence. Then we tried to capture participants' moods after they interacted with each other in a group task, and we looked at the quality of the decisions they made as a group. Meanwhile, whenever there was a lighting condition that could be monitored for power use, that was logged and analyzed. We wanted to see how much energy was used and whether energy use would increase or decrease when workers had control."

The researchers rented office space and furnished it attractively to make it a comfortable environment for the participants. Centrally located in downtown Albany, New York, the office was intended to be easy for the temporary workers recruited by Manpower to reach. "This was a big study with a lot of people working for a lot of hours," Hunter says. "It wasn't easy to get people to participate. I think we were Manpower's biggest client for months as they worked to find the right number of qualified people to serve."

Second-year lighting student Michael Myer also worked on the project. He describes it as a rewarding experience but a challenging one. "I started in May getting the space ready. I installed lighting equipment, checked the software, and coordinated everything. In mid-July I made up the schedule and coordinated the changing lighting conditions. I had to know which participants were coming on what days and when they would come back. I also worked with Manpower on getting the participants there. We all worked some long hours—six days a week sometimes—and we pulled some all-nighters. I trained participants on how to use the computer equipment, and I compiled the data files to send to our research partners in Canada."

Myer sees his participation in the study as a valuable part of his education at the LRC. "It was a great lesson in the problems of real-world research," he says. "I was surprised how much time the research took, and all the problems we had to solve, like participants not showing up when they were scheduled. I learned to be more patient. I learned about the difficulty of writing instructions for people, and even giving directions to participants to find the study site. And I learned how crucial it is to have good data management. You really have to be organized and stay on top of things."

Myer continues, "Another thing I learned about the real world of lighting design is that nothing's ever right. You have to check up on things, and you have to take steps to be sure the installers and the electricians have what they need. Everything may look great on paper, but it's not necessarily going to work when you get it to the site." He observes, "Reality can just kill you! I learned proper design of luminaires and the difference between seeing lighting designs in books and in practice. Working with a real installation helps you start to notice the space and what's good and what's not and what's missing."

Boyce says, "There are several other people who deserve mention for this project: Carol Jones at Battelle is the project manager we worked with at the LightRight Consortium. Also, the lighting designs we used were approved by Jim Benya, Naomi Miller, and Michael White."

Boyce has high hopes for the project. "If there is a link between better office lighting and office productivity," he says, "I think this will be the study to prove it." Data collection is now complete, analysis is underway, and the final report should be available by May 2003.

About the LRC

The Lighting Research Center (LRC) is part of Rensselaer Polytechnic Institute and is the leading university-based research center devoted to lighting. Founded in 1988, the Lighting Research Center has built an international reputation as a trusted and reliable source for objective information about lighting technologies, applications, and products. Its mission is to advance the effective use of light and create a positive legacy of change for society and the environment



2003 Rensselaer Polytechnic Institute, Troy, NY 12180 USA.

Rennselear Polytechnic Institute