The following series of quotes is taken from a variety of sources, including academic papers, research reports, and journals and other publications. They relate to software and website usability issues and are arranged under group headings.

Why You Need Usability Expertise
Improve Product Sales
Cost Justifying Usability
Save Support and Maintenance Costs
Reduce Development Costs and Time
Increase Productivity
Increase Project and Product Success
References
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Why You Need Usability Expertise.
1. There was an awareness of usability before the Web, but business executives and engineers thought anyone could do it. The Web made people realise that usability was desirable but not easy. Source Gilmore, IDEO, 2001.
2. In new economy products for the Web, the user experience is the brand. Source Rubin, 2002.
3. E commerce shifts the emphasis from the advantages of being usable to the penalties of not being usable. Source Hughes, 2002.
4. Clients should insist on usability testing of all Web designs: The quality of the proposed usability process is one of the few ways a client can judge the quality of the end result while still in the proposal stage. A proposal without usability engineering milestones, or with poorly defined or misguided methodology, will result in a poor site most of the time, unless you are in the lucky 10%. Source Manning, McCarthy, Souza, 1998.

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Improve Product Sales.
1. In one survey, 28% of Web shoppers had trouble finding the product they wanted and 62% of Web shoppers gave up looking for a product on line. Source Seminerio, 1998.
2. E commerce sites lose almost half of their potential sales because users cannot use the site. In other words, with better usability, the average site could increase its current sales by 79%. Source Nielsen, 2001.
3. 44% of websites users do not succeed in finishing their purchase on e business websites. Source Nielsen, 2001.
4. Websites must be easy to use. Hard to use sites frustrate customers, forfeit revenue to on line retailers, and erode the image of the company's brand. Source Manning, McCarthy, & Souza, 1998.
5. At Digital, 20 of the most serious usability problems were fixed in the second release of a product. The revenues grew by 80%, which was 66% greater than the projected growth. The customers repeatedly pointed to usability as one of the most significant changes in the product. Source Wixon and Jones, 1991.
6. Interface design features can produce variations of up to 88% in site traffic and 76% in sales. Source Lohse and Spiller,1998.
7. Product list navigation features that reduce purchasing time account for 61% of a variance in sales. Source Lohse and Spiller, 1998.
8. 40% of the users do not return to a site when their first visit resulted in a negative experience. Source Forrester, 1998
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Cost Justifying Usability.
1. Systems design with usability engineering has typically reduced the time needed for training by around 25%. Source Landauer, 1995.
2. 80% of all software development costs occur after the product has been released. Source Karat 1993.
3. User centred design typically cuts errors in user system interaction from 5 percent down to 1 percent. Source Landauer, 1995.

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Save Support and Maintenance Costs.
1. 80% of maintenance is due to unmet or unforeseen user requirements; only 20% is due to bugs or reliability problems. Source Pressman 1992.
2. Microsoft tracks its support call costs and has seen a significant cost savings resulting from improving the usability of its products, such as Word. Source Reed, 1992.
3. Design changes due to usability work on one project at IDS/American Express resulted in estimated savings of $45 million. Source Chalupnik and Rinehart 1992.
4. In order to meet its customer support call needs, WordPerfect had to employ over 900 customer response specialists. Source Reed, 1992.
5. Design changes from one usability study at Ford Motor Company reduced the number of calls to the help line from an average of 3 calls to none, saving the company an estimated $100,000. Source Kitsuse, 1991.
6. 80% of software life cycle costs occur during the maintenance phase. Source Pressman, 1992.
7. The cost of change is 1 unit in the definition phase, 1.5 to 6 units during the development phase, and 60 to 100 units after release. Source Pressman, 1992.

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Reduce Development Costs and Time.
1. Usability engineering has demonstrated reductions in the product development cycle by over 33 to 50%. Source Bosert, 1991.
2. 63% of all software projects overran their estimates, with the top 4 reasons all related to usability. Source Lederer and Prasad, 1992.
3. The percentage of software code that is devoted to the interface has been rising over the years, with an average of 47 to 60% of the code devoted to the interface. Source MacIntyre et al, 1990.
4. Ricoh found that 95% of the respondents to a survey never used three key features deliberately added to the product to make it more appealing. Customers either didn't know these features existed, didn't know how to use them, or didn't understand them. Source Nussbaum and Neff, 1991.

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Increase Productivity.
1. The average software program has 40 design flaws that impair employees' ability to use it. The cost in lost productivity is up to 720%. Source Landauer, 1995.
2. Design changes due to usability work at IBM resulted in an average reduction of 9.6 minutes per task, with a projected internal savings at IBM of $6.8 Million in 1991 alone. Source Karat, 1990.
3. Every computer user suffers a constant series of small frustrations that ...add up to trillions of dollars in lost productivity. Source Kreitzberg, 2002.

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Increase Project and Product Success.
1. More than 30% of software development projects are cancelled before completion, primarily because of inadequate user design input. The result is a loss of approximately $80 billion annually to the economy. Source Standish Group, 1995. 2. The top two reasons projects fail is lack of user involvement and lack of requirements. Source Standish Group, 1995.