lack of standards, cost and speed issues, a Yankee While a myriad of issues warrant attention, we focus on Group [12] survey suggests that U.S. consumers are an area that has been largely neglected--usability and not convinced they want or need mobile services and the user interface experience. We began this artide with think i too con plicated. This is in con- several quotations Iting the fact that issues of trast to other global markets in Asia and Europe where usability have been of interest for over a century. While going online" means reaching for a mobile handset, easy to use, the telephone was limited in use to voice not turning on a PC. In Korea, for example, reports communication. Today, the commercial benefit of suggest that one-third of all mobile phone subscribers understanding and improving the usability of wireless use their handsets for m-commerce activities [6 Web interfaces--delivered via mobile devices such as e In the U.S., despite the touted benefits of m-com- cell phones and PDAs--by consumers is enormous rce, several large companies are abandoning(Wells Fargo) or scaling back U.S.based wireless efforts to Usability and the User Interface focus on global markets (Amazon. com). Yet, carriers The user interface is the environment in which online and content partners are still investing and bright spots users conduct communication, information search, exist. EBay recently launched a new service that lets and transactions [3]. Thus, an important prerequisi customers bid more easily from mobile devices. for the success of e-commerce and m-commerce sites is According to a Yankee Group report[12], the new ser- ensuring that customers' experience, via the interface, vice has the correct success factors-priced right, speed, satisfies both their sensory and functional needs. Stud and ease of use ies have shown, for example, that user interface fea- Like e-commerce, m-commerce represents a huge tures, such as page and content design, are key opportunity for businesses to connect to consumers. determinants of sales in online stores [2].Yet,m-com- ASSESSING USABILITY (relative importance)of the MUG categories/subcat- We used a holistic measure of usability to compare egories across industries and access devices(PC vs. perceptions of wired and wireless Web sites. Th mobile handset) measure and instrument(see [1] for details regard Two sites each were chosen from each of four ing the metric and the instrument) are based on the industries: banking, news, shopping, and tourism, Microsoft Usability Guidelines (MUG; see [7]) representing both informational and transactional Briefly, MUG comprises five main categories: content oriented sites. The sites chosen had a Web site (informational and transactional capabilities of a accessible via a browser and a wireless site accessi site), ease of use(cognitive effort required in using ble via a WAP-enabled device. Since we were inter a site), made-for-the-medium(tailoring a site to fit ested in seeking participation from users who had a particular users needs), promotion(advertising of experience with the Internet as well as data-ori- a site), and emotion (affective reactions invoked by ented features on wireless devices, the study was a site). Each main category, except for promotion, conducted in a downtown movie theatre complex in has associated subcategories. Category/subcategory Helsinki, Finland. Briefly, participants(812 in total) examples include: contentrelevance (pertinence of browsed sites using a kiosk and responded to a the content to audience); ease of use/structure questionnaire. Specifically, the participants were Organization of the site); made-for-the-medium/ first prompted to provide their perceptions of the personalization(technology-oriented customization weights of the different categories/subcategories for of the site); emotion/plot(how the site piques a Web and wireless sites in a particular industry. An user's interest). Application of the MUG involves the aggregation across participants provided the mean omputation of usability by taking into account an weights for all sites in that industry. Then, the par individual's weighting of each category/multiple ticipants visited both the web(using a PC browser) subcategories and his or her rating (evaluation) of a and wireless(using a cell phone emulator) sites and site on the particular category/subcategories rated them on each of the different mug cate Itegories on a 10-poin How the Field Study was Conducted usability rating for each Web site(for a user)was ermined by computing perceptions of the usability of web and wireless sites ratings. An aggregation of the ratings across users details of the study design see [11]). The provided the mean ratings for a particular site within study allowed us to compare and contrast the weights each industry 54 December 2003/Vol 46, Ne. 12 COMMUNICATIONS OF THE ACM54 December 2003/Vol. 46, No. 12 COMMUNICATIONS OF THE ACM lack of standards, cost and speed issues, a Yankee Group [12] survey suggests that U.S. consumers are not convinced they want or need mobile services and many think it is simply too complicated. This is in con￾trast to other global markets in Asia and Europe where “going online” means reaching for a mobile handset, not turning on a PC. In Korea, for example, reports suggest that one-third of all mobile phone subscribers use their handsets for m-commerce activities [6]. In the U.S., despite the touted benefits of m-com￾merce, several large companies are abandoning (Wells Fargo) or scaling back U.S.-based wireless efforts to focus on global markets (Amazon.com). Yet, carriers and content partners are still investing and bright spots exist. EBay recently launched a new service that lets customers bid more easily from mobile devices. According to a Yankee Group report [12], the new ser￾vice has the correct success factors—priced right, speed, and ease of use. Like e-commerce, m-commerce represents a huge opportunity for businesses to connect to consumers. While a myriad of issues warrant attention, we focus on an area that has been largely neglected—usability and the user interface experience. We began this article with several quotations highlighting the fact that issues of usability have been of interest for over a century. While easy to use, the telephone was limited in use to voice communication. Today, the commercial benefit of understanding and improving the usability of wireless Web interfaces—delivered via mobile devices such as cell phones and PDAs—by consumers is enormous. Usability and the User Interface The user interface is the environment in which online users conduct communication, information search, and transactions [3]. Thus, an important prerequisite for the success of e-commerce and m-commerce sites is ensuring that customers’ experience, via the interface, satisfies both their sensory and functional needs. Stud￾ies have shown, for example, that user interface fea￾tures, such as page and content design, are key determinants of sales in online stores [2]. Yet, m-com￾ASSESSING USABILITY We used a holistic measure of usability to compare perceptions of wired and wireless Web sites. The measure and instrument (see [1] for details regard￾ing the metric and the instrument) are based on the Microsoft Usability Guidelines (MUG; see [7]). Briefly, MUG comprises five main categories: content (informational and transactional capabilities of a site), ease of use (cognitive effort required in using a site), made-for-the-medium (tailoring a site to fit a particular user’s needs), promotion (advertising of a site), and emotion (affective reactions invoked by a site). Each main category, except for promotion, has associated subcategories. Category/subcategory examples include: content/relevance (pertinence of the content to audience); ease of use/structure (organization of the site); made-for-the-medium/ personalization (technology-oriented customization of the site); emotion/plot (how the site piques a user’s interest). Application of the MUG involves the computation of usability by taking into account an individual’s weighting of each category/multiple subcategories and his or her rating (evaluation) of a site on the particular category/subcategories. How the Field Study Was Conducted Our field study was designed to explore consumers’ perceptions of the usability of Web and wireless sites (for full details of the study design see [11]). The study allowed us to compare and contrast the weights (relative importance) of the MUG categories/subcat￾egories across industries and access devices (PC vs. mobile handset). Two sites each were chosen from each of four industries: banking, news, shopping, and tourism, representing both informational and transactional oriented sites. The sites chosen had a Web site accessible via a browser and a wireless site accessi￾ble via a WAP-enabled device. Since we were inter￾ested in seeking participation from users who had experience with the Internet as well as data-ori￾ented features on wireless devices, the study was conducted in a downtown movie theatre complex in Helsinki, Finland. Briefly, participants (812 in total) browsed sites using a kiosk and responded to a questionnaire. Specifically, the participants were first prompted to provide their perceptions of the weights of the different categories/subcategories for Web and wireless sites in a particular industry. An aggregation across participants provided the mean weights for all sites in that industry. Then, the par￾ticipants visited both the Web (using a PC browser) and wireless (using a cell phone emulator) sites and rated them on each of the different MUG cate￾gories/subcategories on a 10-point scale. The usability rating for each Web site (for a user) was determined by computing the sum of the weighted ratings. An aggregation of the ratings across users provided the mean ratings for a particular site within each industry. c