Task analysis (TA) is a systematic method for understanding how users perform activities to achieve a specific goal, providing a detailed breakdown of the actions, decisions, and information involved in a process. TA is fundamental across fields like human factors engineering, instructional design, and user experience (UX) design. It is a family of techniques categorized by their focus: observable physical steps, non-observable cognitive processes, or the surrounding context and environment. These methods inform system design, improve training programs, and enhance efficiency.
Defining the Scope and Goals of Task Analysis
The primary purpose of task analysis is to simplify complex activities by dissecting them into manageable components to reveal how they are performed. A key goal is to inform system design and training development by identifying potential pain points and inefficiencies in a workflow. The analysis captures details about the inputs, outputs, tools, time constraints, and information users require, helping to pinpoint areas likely to produce human error and allowing designers to develop error mitigation strategies.
Category One: Analyzing Physical and Procedural Steps
This category concentrates on observable actions, sequences, and measurable steps, making these methods effective for tasks that are structured and repeatable. They document the sequence of overt behaviors and interactions with tools or systems. These methods are often used to develop standard operating procedures or technical manuals where the correct order of steps is paramount for efficiency and compliance.
Hierarchical Task Analysis (HTA)
Hierarchical Task Analysis (HTA) systematically breaks down a complex goal into a hierarchy of sub-tasks and operations. This decomposition creates a tree-like structure, where the main goal is progressively broken down into smaller, granular steps. A defining feature of HTA is the inclusion of “plans,” which are rules describing the conditions and ordering under which sub-tasks should be executed.
Procedural Task Analysis
Procedural Task Analysis is a straightforward method used for tasks that must follow a strict, linear sequence of actions. It is commonly employed for documenting technical processes, equipment operations, or safety procedures where the correct order of steps ensures accuracy. The output is typically a simple, step-by-step list, suitable for creating training manuals and routine checklists.
Workflow Analysis
Workflow analysis focuses on the flow of tasks and information across various roles, systems, or departments, rather than just the steps of one individual user. This method maps the entire process, revealing the interdependencies and handoffs between different actors or components within a system. It helps identify bottlenecks and inefficiencies in the overall organizational process.
Category Two: Investigating Cognitive Processes
This category is designed to uncover the non-observable mental activities that underlie performance, such as decision-making, memory retrieval, and problem-solving. These methods are tailored for knowledge-intensive tasks where errors arise from poor judgment or flawed mental models rather than physical execution failures. They aim to elicit the tacit knowledge that experts use to perform complex work successfully.
Cognitive Task Analysis (CTA)
Cognitive Task Analysis (CTA) is the overarching methodology for analyzing tasks that involve significant mental effort, often in high-consequence environments like aviation or healthcare. CTA seeks to map the thought processes of experts by identifying their goals, interpretations, and problem-solving strategies. The analysis focuses on cognitive demands, such as situational awareness and the development of mental models, often informing training programs that enable novices to acquire expert judgment.
Goals, Operators, Methods, and Selection rules (GOMS)
GOMS is a formalized, predictive model used in human-computer interaction (HCI) to analyze and predict the performance of expert users in routine cognitive tasks. The model breaks down a task into four components: Goals (what the user aims to accomplish), Operators (the lowest-level actions), Methods (sequences of operators), and Selection Rules (rules for choosing among methods). GOMS models are predictive because they assign fixed execution times to operators, allowing analysts to calculate the time an expert user will take to complete a task without errors.
Critical Decision Method (CDM)
The Critical Decision Method (CDM) is a specific interview technique used within the CTA family to capture decision points and cues used by experts during challenging, non-routine incidents. The technique involves a semi-structured interview where the analyst uses cognitive probes to elicit details about how the expert formulated their decision-making strategy in a past, high-stakes situation. By focusing on actual incidents, CDM helps reveal the subtle perceptual cues and mental models that underlie proficient performance in time-pressured settings.
Task Analysis Focused on Context and Environment
Task analysis methods in this category prioritize the surrounding environment, social context, and the tools used, recognizing that task performance is heavily influenced by external factors. This approach, often called contextual task analysis, moves beyond the steps of a single user to examine the broader system in which the work occurs. Contextual analysis involves observing users in their natural work environment to understand how physical constraints, interruptions, and the use of other tools shape their behavior. The analysis aims to identify environmental factors that affect decision-making, ensuring that system designs are realistic and usable within the actual setting.
Choosing the Right Task Analysis Method
Selecting the appropriate task analysis method depends primarily on the purpose of the analysis and the nature of the task being investigated. For optimizing highly structured, repeatable processes, methods like Hierarchical Task Analysis or Procedural Task Analysis are suitable, focusing on mapping observable action sequences. When the objective is to understand expert performance in complex tasks involving significant judgment, a Cognitive Task Analysis approach, such as the Critical Decision Method, is necessary to uncover tacit knowledge. If the analysis must inform the design of a system that integrates into a real-world setting with multiple tools and social dynamics, a Contextual Task Analysis provides the necessary environmental perspective.