Empirical data on the necessity of for and effectiveness of universal design for increasing independence is minimal. There is an abundance of theories for the need of modifications to the environment to fit the needs of people. There is a lack of research to support these theories however.
In my quest to find data, I came across a very unique study conducted in 1999 comparing 2 bathroom layouts with a variety of users. An accessible bathroom is put to the test side by side with a standard bathroom which is not in compliance with accessibility standards.
The results of the study may or may not surprise you. Either way, the outcome of this study is valid for today’s living environments, and can help support the movement for widespread use of universal design concepts.
The following is a summary of a research article published in the ProQuest Psychology Journals in 1999, titled: Measuring Universal Design: Case of the Bathroom. Authored by: Abir Mullick, Associate Professor at State University of New York at Buffalo.
-Universal design has its roots in the design for disability or for the aged, so there is a belief that universal design is the same thing. However, it is a very different from both of those concepts.-Contemporary residential bathroom design generally follows a 2-stream approach: bathroom designed for people with disabilities and bathrooms designed for able-bodied people.
-Accessible bathrooms are based primarily on the needs of wheelchair users and do not address the needs of people with other disabilities.
-It is assumed that accessible bathrooms improve functional independence for people with disabilities and that able-bodied people do not have the need for improved functional
performance.
-The results of the study provide information about the properties that make environments accessible or universal.
Primary objectives:
-Determine how accessible and conventional bathrooms (both code complying and not) improve functional performance of many groups of users.
-Identify, if any, the level of functional independence offered by accessible bathrooms to people without disabilities and other users.
-Evaluate consumer perceptions of bathroom features.
Discussion:
Generalized Results:
1) An accessible bathroom based on current codes greatly improved function independence of people with disabilities, marginally improved the functional independence of all users and did not improve the functional independence of able-bodied users.
2) Accessible fixtures, primarily designed to provide access for people with disabilities, result in a higher level of performance or no difference. They did not diminish performance of any user group.
3) Functional performance is not always directly related to perception of difficulty/ease. For the most part, accessible features that improved performance were perceived as “easy to use”. On may occasions, however, accessible features that did not improve function were also perceived as “easy” to use. On rare occasions, accessible features that improved function were still perceived as “difficult” to use.
4) Accessible features result in either lower or similar level of effort required to perform a task. Many accessible features reduced the effort level to near minimum.
Discussion:
-This study made clear that an accessible bathroom supports people with disabilities and has little or no affect on other users.
-A bathroom based solely on the guidelines of accessible design will have marginal impact on the overall population unless it provides and exceeds the benefits offered by accessible design.
-Many proponents of universal design have suggested that environments that are good for people with disabilities are also good for other people, implying that accessible designs based on the ergonomic considerations of people with disabilities benefit other users.
-Universal design, an inclusive concept, should incorporate and exceed the functional benefits of accessible design by benefiting not only people with disabilities, but also others who do not have any disabling conditions.
-The findings of the study validate the premise of universal design. They also provide information on the design effectiveness of accessible bathrooms and the functional requirements of universal bathrooms.
More details regarding this study below:
Methods:
-Full-scale simulation to evaluate the design effectiveness of 2 existing bathrooms
1) Challenging Bathroom
-Resembled a bathroom in a small apartment that is not in compliance with any current accessibility standards.
Features:
-15 sq.ft. clear floor space
-32″ wide entry door with round knobs and inside swing
-Enclosed vanity, small (20″x20″) counter top, dual knob faucets and high (47″) mirror cabinet
-16″ high toilet with no attached grab bars or wall-mounted grab bars
-15″ high bathtub, fixed showerhead, no wall-mounted grab bars, single knob faucet mounted on-center
2) Supportive Bathroom
-In compliance with the current accessibility standards and included a few universal fixtures such as a fold-able grab bar near the toilet and a large size toggle light switch.
Features:
-25 sq.ft. open floor space
-34″ wide entry door with lever handles and outside swing
-open vanity, larger (20″x30″) counter top, single lever faucet and low (40″) mirror cabinet
-18″ high toilet equipped with wall-mounted grab bar and fold-down grab bars
-roll in shower with a height-adjustable/hand-held shower, wrap around grab bars, and single-lever faucet mounted off-center
-5 sets of design attributes were systematically varied to provide 2 distinct levels of challenge as contexts for the subjects’ performance, including: size of open floor area, entry characteristics, vanity characteristics, toilet characteristics, and bath/shower characteristics.
-32 participants:
+4 mobility impaired females who use wheelchairs
+4 mobility impaired females who do not use wheelchairs
+4 males affected by Multiple Sclerosis
+4 children
+4 young adults
+4 pregnant women
+4 overweight people
+4 well elderly
-The protocol for the research tasks was designed to allow participants make full use of both bathrooms as the participants were asked to simulate the performance of several activities of daily living.
-For each bathroom, participants were asked to enter the bathroom, turn on the light switch, demonstrate use of the toilet, lavatory and bathtub/shower, turn off the light switch, and exit the bathroom.
Measurement:
-Two measures:
1)The “Usability Rating Scale” (URS)
-Has a person rate the perceived ease or difficulty of performing bathroom activities.
-At the end of each task, participants were asked to indicate the level of difficulty/ease they had experienced using the URS scale and the data was recorded in verbal format.
2)The “Environmental Functional Independence Measure” (Enviro-FIM)
-Scores the person’s functional independence while performing the activities.
-Participants were asked to perform the bathroom tasks and their performance was videotaped using wall mounted camcorders.
-The visual data was translated as numerical scores.
-Data analysis of both URS and Enviro-FIM scores were based on the mean scores of activities performed by all participants.
Analysis:
-Analysis involved evaluating the use of the bathroom and the use of the doors, toilet, bath/shower, and lavatory.
-Scores were based on the mean scores of activities performed by all participants.
-Comparisons were made between “able-bodied people” and “people with disabilities”.
Enviro-Fim:
-Scale of 0 to 10: 0=non-performance 10=no assistance
Example:
-Analysis of above: Able-bodied people were generally able to use the bathtub/shower in both bathrooms without any assistance. People with disabilities bathed with safety concerns and were at risk in the challenging bathroom and showered under modified conditions in the supportive bathroom.
URS:
-7-point sliding scale: -3=very difficult +3=very easy
Example:
-Analysis of above: All users perceived bath/shower use in the supportive bathroom to be better than what it is in the challenging bathroom. Able-bodied people perceived greater benefit from using the supportive bathroom than people with disabilities.
***See full article for breakdown of each item analyzed using both Enviro-Fim and URS***
Limitations:
-Generalization is limited due to the small size of research participants.
-Generalization is also limited due to the limited variety of disabilities participants had. There are common disabilities that were not included (i.e. low vision).
Citation:
Mullick, A. (1999). Measuring Universal Design: Case of the bathroom [PDF]. ProQuest Psychology
Journals, 557-562.