An analyst has asked a user to describe each step in a task as they perform it. Which of the following investigation techniques is the analyst using?

Protocol analysis is an investigation technique where an analyst observes a user performing a task and asks them to verbalize their thoughts, actions, and decisions in real-time. This method, often called the "think-aloud protocol," is used to understand the user's cognitive process, problem-solving strategies, and the specific steps they take to complete their work. The analyst's request for the user to "describe each step in a task as they perform it" is the defining characteristic of this technique.

A. Ethnographic study: This is a long-term, immersive observation of users in their natural environment to understand work culture and context, not a single, narrated task performance.
B. Interviewing: This involves a direct question-and-answer session with a user, which is typically conducted before or after a task, not concurrently with its execution.
C. Activity sampling: This is a quantitative technique used to record the frequency and proportion of time spent on different activities at random intervals, not to analyze a single task in detail.

1. Ericsson, K. A., & Simon, H. A. (1993). Protocol analysis: Verbal reports as data. MIT Press. In Chapter 2, the authors detail the methodology, stating that in concurrent verbal reporting, subjects are instructed "to verbalize their thoughts, which are generated anyway in the course of performing the task" (p. xiii, Preface). This directly corresponds to the scenario.

2. Goguen, J. A., & Linde, C. (1993). Techniques for requirements elicitation. In Proceedings of the 1st IEEE International Symposium on Requirements Engineering (pp. 152-164). IEEE. This paper describes protocol analysis as observing "what users do in performing specific tasks" and analyzing the resulting "protocol" of their behavior. It explicitly contrasts this with ethnography, which focuses on the broader social context of work (Section 3.3, p. 156). DOI: https://doi.org/10.1109/ISRE.1993.324824

3. Nielsen, J. (1994). Usability Engineering. Morgan Kaufmann. Chapter 6 discusses the "Thinking Aloud" method, defining it as a process where "you ask test users to use the system while continuously thinking out loud" to understand their thought process (p. 195).