 This video is part three of our series on user engagement research. In our last two videos, we define user engagement, describe user engagement research methods, and explore specific research topics including individual differences and domain knowledge. In this final video, we'll explore task determinability and interest task complexity and search behavior. We'll start with the former. In this study, Capra, Arguello, O'Brien, Lee, and Troy explored task characteristics, task complexity, and user's uncertainty towards a search task. Task characteristics can be defined by their dimensions or attributes. Dimensions can have objective attributes that relate to the task itself, such as how complex or multifaceted a task is, as well as subjective attributes that are based on the user, like what the user knows about the task prior to performing it. Task complexity has been researched from many different perspectives. One view of task complexity involves determining the user's level of uncertainty towards performing the task. Measuring task complexity through user's uncertainty is known as a priori task determinability. In this study, the researchers measured the task complexity of comparative tasks by changing the scope or open-endedness of the task using a priori task determinability. The researchers did this by specifying items such as organic, liquid, and synthetic fertilizers. They then described how the items differ along distinct dimensions such as costs, nutrient content, and health concerns. The researchers found that the most open-ended tasks, which did not have specific items or dimensions to consider, had low determinability, making users less certain about the task. Yet, open-ended tasks were also the least challenging for users who wanted to complete the task quickly. Narrowing the scope of task by only specifying items and not dimensions led to high determinability, making the user more certain about completing the task, which made the task easier. However, specifying dimensions and not items led to low determinability, making the user less certain about the task, which made the task harder. Finally, a qualitative analysis of participants' search queries suggests that searching for dimensions is more challenging than searching for items. Next, we'll explore interest, task complexity, and search behavior. In this study, O'Brien, Arguello, and Capra explored how search tasks with different task topics and task versions affect user engagement. Currently, there's not much research that examines how the complexity of search tasks people perform relate to a user's engagement with digital search systems. In this study, participants completed six search tasks or information searches on different task topics like indoor dog breeds and waste-equipped smoking. These task topics were meant to influence participants' interests in the task. The descriptions of these task topics included or excluded specific items such as types of dogs and dimensions like the height of a certain dog breed at adulthood or how well a certain dog breed handles being home alone. When a search task has items and or dimensions added to it, it becomes more complex or less complex for users. This study included different versions of task topics like what are common indoor dog breeds and how do they differ. These task versions were meant to test users' level of certainty as they planned and completed their search task. Participants self-reported how they perceived the task. For example, they noted how interesting or complex the task was. Researchers also analyzed participants' search engine results and bookmarks. The study found that task topics affected user engagement and perceptions of the tasks such as how interesting, difficult, or important a task was also affected user engagement. However, different versions of task topics did not greatly affect user engagement. Researchers also observed that effort as in performing a task that's considered difficult, negatively impacted engagement. However, bookmarking pages, understanding the task, and understanding how to complete the task led to positive engagement with the search task. This concludes our video series on user engagement research. We hope this information was helpful and thanks for watching.