by Melanie Brunson
In last month's column, I shared the first part of the executive summary from a report that was done for the Bureau of Engraving and Printing, which examined a number of options that would make it easier for people with visual impairments to distinguish between different denominations of U.S. currency. The remainder of this executive summary is below. Key Findings for Tactile Features
Three primary tactile features were included in the usability test. The tested tactile features included a cluster pattern of raised dots, a system of notches cut into the top and bottom edges of the note, and a system of heavy intaglio raised print bars along the side of the note. Usability test results showed that the prototype edge notches were the most accurate means of identifying denomination for blind participants (average of 89 percent accuracy). The raised dot clusters, as implemented in Canadian currency, yielded positive results when the currency was essentially new (average of 84 percent accuracy) but the results for raised dots were significantly degraded on widely circulated notes (average of 49 percent accuracy). The prototype intaglio print raised bars were very helpful when new (average of 85 percent), but had similar results as the raised dots when simulated to be well circulated (average of 42 percent). Usability tests for the other tactile features yielded average accuracy measurements below 75 percent.
Blind participants had a strong preference for the notches feature, though there was some concern about potential degradation of performance with widely circulated notes. Blind participants said that they used the raised intaglio print numerals on Canadian notes as backup for identification when the raised dots were too worn down to identify. Fifty-three percent of the survey participants said they thought a tactile feature would help them denominate currency. In the survey results, 43 percent of all respondents favored multiple accommodations (e.g., combination of a size format and a tactile feature) so that one feature could be used if the other was not discernable. Key Findings for Currency Reader Devices
Three commercially available currency reader devices were evaluated in usability tests: two devices that require the user to slide the note into a slot in the device, and a cell phone camera-based device. In addition, three developmental prototypes were evaluated: two devices that require the user to slide the note into a slot in the device and a cell phone camera-based device. The ARINC team conducted the usability testing between June 2008 and April 2009, using devices that were operational and available at the time. The ARINC team is aware that technical breakthroughs in this marketplace are occurring at a rapid rate, and the manufacturers of the prototypes tested may make changes to the devices before they become commercially available.
Devices currently under development may yield different results than the devices used in this study. Survey participants were asked if they would take a reader with them when they went out in public. The results were not conclusive — 36 percent of all participants said they would, either occasionally or frequently, 23 percent said rarely, while 41 percent said never. The type of device annunciation (e.g., tone, voice, vibration) is an important consideration for blind and VI people. Most participants preferred voice annunciation when using a device at home, but were concerned about the reader revealing the value of the currency to nearby customers. Usability test participants commented that portability and speed of use are important factors in their willingness to use a reader device. One of the prototype devices received high marks for portability; several participants said they would carry something with similar size and speed with them and would use it while standing in line. Timing is critical in this scenario and most blind participants felt that the commercial devices were too slow for validating notes received as change in a transaction.
Slide-in devices varied in ease of use. Proper use of these devices — orienting the note, sliding it in without folded corners, pressing a button and waiting for response—required varying amounts of dexterity. One of the larger devices was the easiest to use for virtually all participants. The smallest device was easy to use for most participants, and was praised for its portability, but was more challenging for those who had dexterity impairments. Participants described the need to orient notes for some devices as inconvenient because orienting the note added to the time it took to denominate the currency. Cell phone-based solutions were fairly easy for most participants to use, but took longer to identify the denomination. Participants considered the high cost of currently available devices to be a barrier to implementation. Economic Analyses of Accommodations
The ARINC team conducted economic analysis of the costs and benefits of seven selected alternative accommodations for blind and VI communities, including: size changes along one dimension, size changes along two dimensions, mechanical tactile features, raised tactile features, embedded tactile features, overt machine-readable features, and currency reader devices. Cost analysis results include initial non-recurring (one-time) and annual recurring costs associated with each accommodation. The ARINC team considered three top-level categories of costs in this study — U.S. government (i.e., the BEP, the Federal Reserve Board (FRB), and the U.S. Secret Service), U.S. market sectors (i.e., commercial banking, automated teller machines (ATMs), vending, transportation, gaming, and retail equipment), and U.S. individuals (e.g., the acquisition costs of reader devices). Cost and Benefit Findings for Note Size Variation
The ARINC team evaluated two size variation approaches, one-dimensional (1-D), where only length varied by denomination, and two-dimensional (2-D), where both length and width varied by denomination. The identified government and industry costs (including initial non-recurring investment and annual recurring cost) for implementing size variation accommodations were relatively high — more than $9.5 billion for the first year of 1-D accommodations and more than $10.6 billion for the first year of 2-D accommodations. Blind participants were able to achieve only moderate denomination accuracy (average ranged between 41 and 73 percent) in usability tests of currency and prototypes with size change accommodations. Distinct two-dimensional note size differences resulted in the highest average speed performance (7.2 seconds) and accuracy (73 percent) for blind usability test participants for all of the currencies and the prototype with 2-D size differences. Cost and Benefit Findings for Tactile Features
The ARINC team evaluated three types of tactile features, mechanical (notches along the edges of the notes), raised (raised dots and printed bars), and embedded (foil patches).
Mechanical. The identified government and industry costs (including initial non-recurring investment and annual recurring cost) for mechanical tactile features were moderately high — more than $6.6 billion. Blind participants were better at denominating currency using notches than size variation features. Most blind participants were able to denominate the system of notches accurately (average of 89 percent) and quickly (average of 14 seconds in initial trials, improving to 8.5 seconds with practice).
Raised. The identified government and industry costs (including initial non-recurring investment and annual recurring cost) for raised tactile features were moderately high — more than $6.6 billion. Usability testing of raised dots and intaglio printed bars showed the benefits of raised tactile features on new notes. Blind participants were able to use the tactile feature to denominate new Canadian notes accurately (average of 84 percent). Intaglio printed bars yielded similar results on new notes (average of 85 percent). However, recognition accuracy for widely circulated notes was significantly reduced for both the raised dots and the intaglio printed bars.
Embedded. The identified government and industry costs (including initial non-recurring investment and annual recurring cost) for embedded tactile features were relatively low — more than $568 million. However, embedded tactile features are of limited benefit because they are typically difficult for blind people to locate. Enhancements to existing embedded features would be required to make embedded features a viable option for currency denomination. Cost and Benefit Findings for Machine-Readable Features
The identified government and industry costs (including initial non-recurring investment and annual recurring cost) for machine-readable features were relatively low — more than $75.8 million. There are no direct benefits to the blind and VI population from machine-readable features, unless devices are specifically developed to work with them, but new machine-readable features could enable manufacturers to develop currency reader device technologies that the blind and VI community would be more inclined to use. Cost and Benefit Findings for Currency Reader Devices
The ARINC team performed a cost analysis and a qualitative benefit analysis of six reader devices (three commercial and three prototype devices) to assess their efficacy as an accommodation for currency denomination by blind people. For the prototype devices, the manufacturers provided an estimated cost, but emphasized that the final price would change based on design changes or estimated market size.
Slide-in note readers provided the greatest benefit among the tested devices. These devices were easiest to learn to use and were very accurate (98 to 99 percent average accuracy) in relatively short times (average results for individual devices ranged from 17.3 to 21.7 seconds). The estimated purchase price of these devices ranged from $100 to $330.
The commercial cell phone reader device, although highly accurate (average 100 percent), provided moderate benefit to blind test participants; the denomination time (average of 34.2 seconds) was slower than they preferred. The estimated purchase price of the device was $1,600, but this device provides other applications in addition to currency identification. The prototype note corner reader was of marginal benefit to the blind test participants because the device accuracy (average 81 percent) was lower and the denomination speed (average of 36.5 seconds) was slower than the other devices tested. The estimated purchase price of the device was $100. The prototype cell phone device was too difficult for the blind test participants to use to be beneficial. The estimated price of $30 covers only the software; a cell phone would need to be purchased separately.