Initial Workflow for Applying KLM
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Task Definition
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The first step in applying KLM is task definition. Can anyone tell me why defining the task clearly is so important?
It helps establish a clear goal for the rest of the analysis?
Exactly! A well-defined task ensures that we know what we are analyzing. It sets the scope for the whole workflow. Remember, without a clear definition, everything else falls apart.
So we need to be specific about every detail of the task, right?
Correct! Specificity allows us to capture the nuances of user interactions, which is the essence of KLM.
To summarize, defining the task brings clarity and structure to our analysis, which is vital for accurate predictions.
Method Decomposition
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Next, we move to method decomposition. Why do you suppose it's critical to break the task into smaller user actions?
Because it allows us to understand all the steps involved in completing the task?
Exactly! Method decomposition helps us identify every action the user takes, which we will need for the next steps.
Does this mean we have to write each action down?
Yes, clearly documenting each observable action ensures we don't overlook anything. This is crucial for accuracy in our analysis.
In conclusion, method decomposition is essential for pinpointing all user actions associated with the task, leading to precise KLM applications.
Preliminary Operator Assignment
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Letβs discuss preliminary operator assignment. How do we determine which KLM operators to assign to each action?
We choose based on what kind of action it is, right? Like whether it's a keystroke or a mouse action?
Exactly! Each action corresponds to a specific KLM operatorβK, P, H, D, M, or R, depending on the physical or cognitive action. This classification is essential for later calculations.
Is there a specific sequence we need to follow while assigning?
Not a strict sequence, but consistency in how you apply the operators is important. It ensures that our final predictions are reliable.
To summarize, accurately assigning KLM operators to user actions is fundamental to obtaining a meaningful analysis of user performance.
Iterative Refinement
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Now, letβs talk about iterative refinement, especially regarding the placement of the 'M' operator for mental preparation. Why is that step challenging?
I think itβs because mental actions can be hard to quantify compared to physical actions.
That's a great point! Mental preparation times are subjective and can vary based on user experience and the complexity of the task. We use heuristics to aid in placing the 'M' operators.
What if we place them incorrectly?
That can lead to inaccurate execution time predictions, which defeats the purpose of using KLM. Hence, careful consideration is vital.
To conclude, refining mental preparation placements is critical for accurate task timing estimations, and leveraging heuristics can help guide us.
Summation for Prediction
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Finally, we reach the summation step. How do we calculate the total predicted execution time?
We sum up the average time durations for each operator in our sequence?
Correct! This total gives us the predicted time for an expert user to complete the task based on our analysis.
What happens if the predicted time is longer than expected?
A longer predicted time might indicate potential inefficiencies in the design, prompting us to revisit specific elements or actions.
In summary, summation of operator times is essential for creating reliable execution time predictions and guiding iterative design improvements.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
The workflow for applying KLM consists of five key steps: defining the task, decomposing it into user actions, assigning appropriate operators, refining mental preparation placement, and calculating total execution time. This structured approach emphasizes the importance of meticulous detail in task analysis and operator assignment to derive accurate predictions of user performance.
Detailed
Initial Workflow for Applying KLM
The Keystroke-Level Model (KLM) provides a framework for analyzing expert user interactions within HCI. To effectively apply KLM, designers should follow a systematic workflow consisting of five essential steps:
- Task Definition: Clearly and unambiguously define the specific routine unit task that will be subjected to analysis. It establishes the foundation for further analysis.
- Method Decomposition: Break down the defined task into a granular, sequential list of user actions, focusing on identifying all observable physical and mental operations involved in task execution.
- Preliminary Operator Assignment: Assign appropriate KLM operatorsβKeystroke (K), Pointing (P), Homing (H), Drawing (D), Mental Preparation (M), and System Response (R)βto each action in the decomposed sequence. This ensures that all relevant user actions are captured accurately.
- Iterative Refinement: Correctly position the 'M' (Mental Preparation) operators using specific heuristics. This step is critical because mental preparation time can vary and require careful consideration based on task specifics.
- Summation for Prediction: Once the complete sequence of operators is established, sum their predefined average duration to derive the total predicted execution time for the task.
By following this structured workflow, designers can optimize user interaction processes, enabling informed improvements in interface design.
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Task Definition
Chapter 1 of 5
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Chapter Content
Clearly and unambiguously define the specific, routine unit task that will be subjected to analysis.
Detailed Explanation
The first step in applying the Keystroke-Level Model (KLM) is to precisely define the task you want to analyze. This means determining exactly what the user will do, ensuring that the task is straightforward and routine. For example, if you choose a task like 'copying text,' specify whether it's moving text from one word processor document to another or copying an email subject line. The clearer the task definition, the easier it is to break down and analyze.
Examples & Analogies
Think of this like planning a road trip. Before you choose your route (the analysis), you need to clearly define your starting point and destination (the task). If you're vague about where you're going, it will be challenging to find the best path.
Method Decomposition
Chapter 2 of 5
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Chapter Content
Break down the defined task into a granular, sequential list of the user's physical and mental actions. At this initial stage, focus on identifying all observable primitive operations.
Detailed Explanation
In this step, you need to take the clearly defined task and break it down into smaller actions or steps that the user will perform. This includes both physical actions (like clicking and typing) and cognitive actions (like deciding what to do next). It's important to focus on all observable actions while ensuring that each step is clear and follows a logical order. For instance, if the task involves copying text, actions might include: 'select the text,' 'press Ctrl+C,' and 'move to the paste location.'
Examples & Analogies
Imagine you're disassembling a piece of furniture for moving. You wouldn't just think about the end result (everything moved). You'd take it apart step-by-step: unscrew the legs, remove the tabletop, and pack the pieces. Similarly, method decomposition means taking the task apart so it can be analyzed piece by piece.
Preliminary Operator Assignment
Chapter 3 of 5
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Chapter Content
Assign the appropriate KLM operators (K, P, H, D, R) to each action in the decomposed sequence.
Detailed Explanation
After breaking down the task into individual actions, the next step is to assign specific Keystroke-Level Model operators to each action in your sequence. KLM defines several operators such as 'K' for keystrokes (pressing a key), 'P' for pointing (moving a mouse pointer), 'H' for hand movements (switching between devices), 'D' for drawing (like creating shapes), and 'R' for system responses. This step helps categorize and quantify each action for later time estimation.
Examples & Analogies
Think of this step like assigning roles in a play. Each actor (operator) has a specific part they need to play within the scene (task). For instance, if one actor's job is to move the set (pointing, 'P') and another is to deliver lines (keystrokes, 'K'), it helps organize the performance logically.
Iterative Refinement (with 'M' heuristics)
Chapter 4 of 5
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Chapter Content
The crucial step of correctly placing the 'M' (Mental Preparation) operators, which often requires careful application of specific heuristics (detailed in the next lecture).
Detailed Explanation
Here, you refine your action sequence by placing the 'M' operators strategically. These 'M' operators represent moments of mental preparation that occur before specific actions, like deciding what to do next. This step often involves applying heuristics or guidelines to determine when a mental preparation is needed in the context of task performance. This might take practice to get right.
Examples & Analogies
Imagine you're a chess player. Before making your move (the physical action), you often pause to think about your strategy (mental preparation, 'M'). Knowing when to pause for thought helps determine the best moves in the game, just like knowing when to place 'M' helps in estimating task performance.
Summation for Prediction
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Chapter Content
Once the complete sequence of operators is defined, sum the pre-defined, average time durations for each operator to arrive at the total predicted execution time.
Detailed Explanation
The final step involves calculating the total predicted execution time for the task by adding up the time estimates for each operator in your defined sequence. Each KLM operator has an average execution time associated with itβthese values can be found in KLM literature. By summing these times, you obtain an overall time prediction that represents how long it will take an expert user to perform the task under ideal conditions.
Examples & Analogies
This is similar to budgeting for a project. You calculate the cost of each component (materials, labor, etc.) and then sum these amounts to get an overall project budget. In KLM, each action's time is the cost, and adding them together gives you the total time needed to complete the task.
Key Concepts
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Keystroke-Level Model: A predictive model for analyzing user performance.
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Task Definition: Identifying the specific task to analyze for better focus.
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Method Decomposition: Breaking down tasks into granular user actions for precision.
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Operator Assignment: Linking user actions with KLM operators for analysis.
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Mental Preparation: Considering the cognitive aspect of user actions.
Examples & Applications
Analyzing the task of entering a password could follow KLM steps to optimize efficient input methods.
Using KLM to compare interface options for a copy-paste task demonstrates its application in real-world scenarios.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
To know KLM, define the task, then break it down, that's what we ask.
Stories
Imagine a chef preparing a meal; she first decides on the dish, breaks the steps into ingredients and tools, assigns the right methods, and then starts cooking.
Memory Tools
D-M-P-I-S: Define, Method, Place, Iterative, Summation - Remember the workflow order!
Acronyms
KLM
for Keystroke
for Level
for Model.
Flash Cards
Glossary
- KLM
Keystroke-Level Model; a model that predicts the time required for expert users to perform routine tasks.
- Task Definition
The first step in KLM application, identifying and clarifying the specific task to analyze.
- Method Decomposition
Breaking down a task into a sequential list of individual user actions.
- Operators
The KLM defined actions (K, P, H, D, M, R) that correspond to user interactions.
- Mental Preparation (M)
Cognitive processes that occur before an observable action, accounted for as 'M' in KLM.
Reference links
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