# A Methodology to Evaluate User Experience for People with Autism Spectrum Disorder
## 5 A Methodology to Evaluate UX for People with ASD
### S2 Execution Stage
#### 5.2.3 S2.3 User Tests  
Once the inspections substage is finished or in parallel, the execution of at least one user test is required. Implementing tests with users' aims to find problems and measure the satisfaction of the participants after their interaction with the system, product, or service. The user testing substage contemplates two methods: field observation and controlled observations. For both evaluation methods we recommend:  
* Informing and instructing the user about the experiment, prior to carrying it out. Information and instructions must be clear and concise, prioritizing textual and/or visual communication. * The interaction with the user, throughout the experiment, must consider the specific characteristics that the participant may present (e.g., not having any contact or physical proximity with people with ASD who may react negatively to this action). * Having the consent of users or tutors (if necessary). Inform users and tutors that all information obtained will be treated anonymously. * Keeping in mind throughout the experiment the dependence and autonomy of each of the participants. Sometimes the participants may require support from a tutor or a professional to help them. * Obtaining the support of one or more tutors in case of any unforeseen event (if necessary). The tutor(s) can guide the user in the tasks to be carried out when necessary and/or assist the evaluators in identifying potential problems that may occur during the execution of the test. * The investigator(s) should take on an observer role. Observers must not interfere during the experiment unless it is strictly necessary. * Recording if the tutors or researchers have had to help the participants or interrupt the experiment, because the results obtained may be different or vary. * Recording interactions with the system, product, or service through audiovisual recordings, always maintaining the anonymity of the user. * Observers must record what they observed during the sessions in writing. We recommend recording the following information [45; 46]: (1) activity performed, (2) actions, events and behaviors observed by users, (3) possible cause of the problem, considering the characteristics of the user, (4) description of the user (to identify the user more quickly in the audiovisual record). More details of each evaluation method are given below. Field observation aims to obtain information from users and detect potential problems of the system, product, or service to be evaluated [39]. These potential problems are detected while observing the user interacting with the system, product, or service in a natural environment. When using the field observation method, we recommend:Scheduling one or more observation sessions for users. Each session must have an estimated duration. * During sessions, users should always be in an environment that is familiar to them. It is for the same reason that it is recommended not to interrupt users' activities and not to distract users by including elements outside their usual environment. Table 12 presents a brief specification of the execution of the field observation method, considering the inputs, execution steps, and outputs (see Appendix A) that are relevant when implementing this evaluation method. Controlled observation aims to identify potential problems that users may experience when interacting with the system, product, or service [39]. Controlled observation consists of the execution of guided activities, to eliminate the noise of the data obtained by including strict controls, such as the ordering of tasks, thus minimizing the possible effects of knowledge transfer between tasks and avoiding repetitive actions. When using the controlled observation method, we recommend:  
* Recording the times that the participants have required to develop each task. * Have a controlled environment, free from noise and visual distractions. If possible, make observations of the user in an appropriate laboratory.