Optimising website design for people with learning disabilities using 'trade-off' analysis

引言来自学术界(如Tarleton，2004)、学习障碍组织(Proud，2008)和政府(DH，2005)的许多文献都强调学习障碍者(LD)积极参与社会。这些愿望只能通过提供可获得和相关的信息--现在越来越多地以电子形式提供--才能实现。尽管电子媒介，特别是互联网可以极大地帮助提供信息(例如，Adam和Tatnall，2008)，但许多材料是学习障碍者无法获得的。这甚至包括“易读”的信息，因为在浏览互联网和获取信息方面存在困难。尽管存在这个问题，但关于哪些设计功能有助于网站使用的证据很少，关于这个问题的建议也是相互矛盾的。例如，Nielson(1996)建议页面足够短，以避免滚动的需要。相比之下，Keates等人(2007)和其他人敦促使用图像。然而，包含此类内容的页面往往更长，因此需要滚动。因此，人们面临着这两种属性之间的“取舍”。这就引出了一个问题：如何才能为学习障碍人士最佳地呈现和组织电子传递的信息？这就是我在这个项目中试图解决的问题。方法论参与者这项研究的重点将是那些有“中度”学习障碍的人。在教育界，这样的群体被描述为“入门”级别(Moser，1999)，在这个级别上的人可以：-阅读和理解简单的文本-遵循简单的说明-从简单的图形(例如安全标志)中获得主要思想。重点领域这将是获取信息，而不是交流或创造内容，并认为信息有助于包容(Tarleton，2004)。重要的是，内容理解将不会被正式衡量--界面上只包括“可访问的”和“可理解的”信息，因为布局和呈现是检查的对象。方法这将涉及网站可用性测试，参与者使用和比较可访问的网站，并关注不同的属性(菜单列表、布局和导航)。任务将只涉及一个动作，因此适合低识字技能的人承担。这些任务将在不同布局的可访问网站上进行(有/没有图像；垂直/水平菜单等)。措施将是：-任务时间：有学习障碍的人注意力持续时间较短(LDAA，2010)，可能不希望花费超过较短的时间查找信息。完成任务的时间将被用来衡量任务的难度，而不是简单地衡量“正确/不正确”的表现--任务将被设定为完全在参与者的能力范围内，这样他们就不会感到不舒服或害怕。该指标已经被用于涉及学习障碍人士的可用性研究(例如，Karreman等人，2007年)，并且是其他可用性研究的标准指标。-偏好：显然，没有吸引力的资源将被充分利用。我希望在项目中包含偏好数据还有一个更具哲学性的原因。这是因为“包容”包含了自我倡导和选择的理念。分析将采用联合分析或“权衡”分析。这是一个在市场研究中使用的套餐，以前从未在这种情况下使用过。联合将决定网站的哪些属性(文本大小；菜单位置)对性能的影响最大，以及影响程度有多大。因此，这种技术显示了最优的场地设计，考虑了所有研究的属性的组合。这些发现将提供一幅丰富的图景，说明如何最好地通过电子方式为学习障碍人士提供信息。

IntroductionMuch literature from academia (e.g. Tarleton, 2004), learning disabilities organisations (Proud, 2008) and government (DH, 2005), emphasises the active involvement in society of people with Learning Disabilities (LD). These aspirations can only be achieved by the provision of accessible and relevant information - now increasingly available in electronic form.Although the electronic medium, and in particular, the Internet, may greatly assist information provision (e.g. Adam and Tatnall, 2008), much material is out of reach of people with learning disabilities. This includes even 'easy-read' information, because of difficulties in navigating the Internet and accessing the information. Despite this problem, there little evidence regarding what design features aid website use, and advice on the subject is conflicting. Nielson, (1996), for example, recommends pages short enough to avoid the need to scroll. By contrast, Keates et al (2007) and others, urge the use of images. Pages containing such content, however, tend to be longer and therefore require scrolling. Thus one is faced with a 'trade-off' between the two attributes.This leads to the question: how can electronically delivered information be optimally presented and organised for people with learning disabilities? This is what I seek to address in this project.MethodologyParticipantsThe study will focus on those having 'moderate' learning disabilities. Such a cohort is described in educational circles as being at the 'Entry' level (Moser, 1999) People functioning at this level can:-Read and understand simple text-Follow simple instructions-Get the main idea from a simple graphic (e.g safety signs).Area of focusThis will be on access to information, rather than communication or creating content, and takes the viewpoint that information aids inclusion (Tarleton, 2004). Importantly, content understanding will not be formally measured - only 'accessible' and 'comprehensible' information will be included on the interfaces, as the layouts and presentation are the subject of examination. MethodThis will involve website usability testing with participants using and comparing accessible websites, and focusing on different attributes ('menu' lists, layout and navigation). Tasks will involve only one action, and are thus suitable for undertaking by people with low literacy skills. The tasks will be undertaken on accessible websites of different layouts (with/without images; vertical/horizontal menus etc.). Measures will be:-Time on task: People with learning disabilities have short attention spans (LDAA, 2010) and may not wish to spend more than a short time finding information. Time on task will be used as a measure of task difficulty, rather than the simple measure of 'correct/incorrect' performance - tasks will be set that aim to be well within the ability range of the participants so they do not feel uncomfortable or intimidated. The measure has already been used in usability studies involving people with learning disabilities (e.g. Karreman et al, 2007) and is a standard measure in other usability studies.-Preferences: Clearly, a resource that does not appeal will be underused. There is also a more philosophical reason why I wish to include preference data in the project. This is because 'Inclusion' encompasses the idea of self-advocacy and choice.AnalysisConjoint or 'trade-off' analysis will be employed. This is a package used in market research and never before exploited in this context. Conjoint will both determine which attributes (text size; menu position) of a site have the greatest impact on performance, and by how much. Thus this technique shows the optimum site design, taking into account combinations of all the attributes studied. The findings will provide a rich picture of how information for people with learning disabilities may be best facilitated electronically.