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Three Methods of Usability-UX Task Analysis, REM, UX System Diagrams

Authored by: Toshiki Yamaoka

Handbook of Usability and User Experience

Print publication date:  May  2022
Online publication date:  May  2022

Print ISBN: 9780367357702
eBook ISBN: 9780429343490
Adobe ISBN:

10.1201/9780429343490-4

 

Abstract

The usability-UX (User Experience) task analysis, REM (hierarchical Requirements Extraction Method) and UX system diagram proposed are new methods for collecting usability and UX. As new products or systems related to service design become more complex in the 21st century, three new logical methods for usability and UX to extract user requirements are required. Usability-UX task analysis is designed based on the task analysis to extract user requirements systematically and quantitatively from the viewpoint of the good and bad points of a task. REM is a method for extracting user requirements by root cause and final purpose based on the problems of products or systems. UX system diagrams can create UX and feelings based on the four attributes of product, story, feeling and sense by UX.

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Three Methods of Usability-UX Task Analysis, REM, UX System Diagrams

3.1  Introduction

The usability-UX (User Experience) task analysis, REM(hierarchical Requirements Extraction Method)and UX system diagram are proposed as new methods for collecting usability and UX. Usability-UX task analysis is a variation of task analysis allowing user requirements to be obtained systematically and quantitatively. REM is a method for extracting user requirements by root cause and final purpose based on problems of products or systems. UX system diagrams can create UX and feelings based on the four attributes of product, story, feeling and sense by UX. As new products or systems related to service design become more complex in the 21st century, new logical methods for usability and UX to extract user requirements are required. This is because most existing methods depend on intuition and personal ability, and so they seem to not be useful or effective for complex systems such as service design, social design and so on, which are needed in the 21st century.

3.2  Usability-UX Task Analysis (Yamaoka 2012)

3.2.1  Background and Purpose

Usability and UX have become very important elements in the creation of attractive products, GUIs and services. However, designers and engineers cannot get information on usability and UX efficiently and systematically. Usability-UX task analysis is used for collecting user requirements and UX etc. in an efficient and systematic manner. This method is constructed based on task analysis which can obtain problems regarding tasks for products and is a popular technique in ergonomics. The usability and UX data extracted by this method can be analyzed using qualitative and quantitative methods such as multiple regression analysis, FCA (formal concept analysis) and so on.

3.2.2  Proposed Method

Usability-UX task analysis was developed based on task analysis to get user requirements systematically and quantitatively from the viewpoint of the good and bad points of a task (Figure 3.1). Task analysis is a very important method to extract user requirements or problems for each task.

Figure 3.1   Usability-UX task analysis.

The procedure of collecting user requirements is as follows.

  1. The test participants evaluate each task of products, GUIs and services.

Each task is evaluated from the viewpoint of the good and bad points of usability, and the UX of the task. Test participants are asked to fill out appropriate evaluation words in the blanks in a Sentence Completion Test (SCT) after operating the products, GUIs and services. SCT is aimed at collecting the causal relationship of the usability of the task (Figure 3.2).

Figure 3.2   SCT (Sentence Completion Test).

The tasks of products are evaluated from the viewpoint of UX according to a three-grade evaluation: good, ordinary and bad. And they also are evaluated from the viewpoint of usability (good and bad points) according to the Likert scale: strongly agree (5), agree (4), neutral (3), disagree (2) and strongly disagree (1).

  1. After each task is done, synthetic evaluation is finally conducted as mentioned above.
  2. The good and bad points are analyzed.

The good points become user requirements, while the bad points are changed into good user requirements. For example, a bad point of “heavy” is changed into user requirement “light,” which is an antonym of “heavy.” The idea of including the two words with positive and negative comments is a very important user requirement.

  1. Qualitative analysis

User requirements including UX are collected and structured.

As user requirements are collected and structured by grouping, very important user requirements are selected.

  1. Quantitative analysis

User requirements are also analyzed using statistical methods. Multiple regression analysis of usability can be done using the five-grade evaluation data of the Likert scale. UX can also be analyzed using the three-grade evaluation data by multiple regression analysis.

3.3  Example of the Application of Usability-UX Task Analysis

A web screen of six hotels and three mechanical pencils (Figure 3.3) was evaluated and analyzed using usability-UX task analysis. Six university students (female, 20–26 years old) answered questions on tasks for a web screen of six hotels (Figure 3.4), and eight university students (female, 20–26 years old) answered questions on tasks for three mechanical pencils (Figure 3.5).

Figure 3.3   Three mechanical pencils.

Figure 3.4   An example of usability-UX task analysis of a web screen (shown as a part of a web screen of six hotels and three tasks).

Figure 3.5   Usability-UX task analysis of a mechanical pencil (shown as a part of three mechanical pencils and three tasks).

The test participants checked all of the tasks of the products and screens as the synthetic evaluation and grade (Table 3.1).

  1. Four screens such as the home page, guest rooms, accommodation plans and ideal plans were selected as tasks. Table 3.2 shows some of the results for the usability-UX task analysis of six hotels.
  2. Four tasks for the mechanical pencils such as picking up the pencil, holding it, clicking it and writing were selected. Table 3.3 shows some of the results for the usability-UX task analysis of the three mechanical pencils.

Table 3.1   User Requirements Collected from Synthetic Evaluation

The requirements collected in synthetic evaluation

Requirements organized as good points

Important requirements

Requirements organized as bad points

Light and easy to write

Writing easily important

Difficult to write

Light and easy to hold

Holding easily is important

Heavy and tired to hold

Friendly

Fit in hand

Fitting in hand is important

Doesn't fit in hand

High-grade image

High-grade image is important

Cheap-looking

Table 3.2   UX Items Collected in the Writing Task

UX organized as good points

Important requirements

UX organized as bad points

Light and easy to write

Writing is an important requirement

Difficult to write

Smooth and easy to write

Smooth is an important requirement

Not smooth

Easy to hold

Holding easily is an important requirement

Thin and difficult to hold

Table 3.3   Average (AV) and Standard Deviation (SD) of User Requirements of Mechanical Pencils A, B and C

Average and standard deviation of user requirements

Task 1

Task 2

Task 3

Task 4

Synthetic evaluation of user requirements

Picking up mechanical pencil

Holding mechanical pencil

Clicking mechanical pencil

writing

AV

SD

AV

SD

AV

SD

AV

SD

AV

SD

A

3.14

0.70

3.42

0.98

2.71

1.38

2.57

1.13

3.00

1.00

B

3.00

1.15

2.57

0.79

2.43

1.27

2.57

1.51

2.71

0.76

C

3.00

1.00

2.43

0.53

3.57

0.98

4.29

0.76

3.57

1.13

The collected usability and UX were structured and analyzed.

Collected data was structured and analyzed by average, standard deviation and multiple regression analysis.

3.3.1  Structuring of the Data

The requirements or UX collected regarding the good points and bad points from synthetic evaluation were grouped (Tables 3.1 and 3.2). When the requirements or UX based on good points were opposite to the requirements based on bad points, the requirements or UX became very important. When “being easy to write” as a good point and “being difficult to write” as a bad point were selected for an example, they were opposite to each other and then “writing easily” became the important requirement.

3.3.2  Analysis of the Data

  1. Average, Standard Deviation

The average and standard deviation of user requirements and UX of mechanical pencils A, B and C were calculated (Tables 3.3 and 3.4). When the numerical value of the average is high, the average of user requirements and UX means a good evaluation. If the numerical value of the standard deviation is high, the standard deviation of user requirements and UX shows that the opinions of participants were divided. Mechanical pencil C had generally high scores in the average and UX, but the standard deviation was also high and the opinions were divided. As mechanical pencil C is designed for drawing, it is heavy and substantial compared with the other mechanical pencils.

  1. Multiple Regression Analysis

Table 3.4   Average (AV) and Standard Deviation (SD) of UX of Mechanical Pencils A, B and C

The average and standard deviation of UX

Task 1

Task 2

Task 3

Task 4

Synthetic evaluation of user requirements

Picking up mechanical pencil

Holding mechanical pencil

Clicking mechanical pencil

Writing

AV

SD

AV

SD

AV

SD

AV

SD

AV

SD

A

2.29

0.49

2.57

0.53

2.00

0.82

2.29

0.76

2.14

0.38

B

2.43

0.79

2.43

0.53

1.57

0.79

1.86

0.90

2.00

0.82

C

2.29

0.76

1.86

0.90

2.57

0.79

2.71

0.49

2.43

0.98

Multiple regression analysis was done to extract important user requirements and UX (Tables 3.5 and 3.6). As mechanical pencil A is light, relatively ordinary and high scoring, the important task to influence synthetic evaluation was clicking regarding use requirements and holding regarding UX. Mechanical pencil B has a special clicking button located in the middle of the body in order to push while writing. This special function made it lower in evaluation. Mechanical pencil C is heavy and substantial compared with the other mechanical pencils, and so it had a high score.

  1. Formal Concept Analysis

Table 3.5   Important Tasks to Influence Synthetic Evaluation Regarding User Requirements

Explanatory variable

Response variable

Task 1

Task 2

Task 3

Task 4

Synthetic evaluation of user requirements

Picking up mechanical pencil

Holding mechanical pencil

Clicking mechanical pencil

Writing

Mechanical pencil A

—

—

✓

—

Mechanical pencil B

—

—

—

✓

Mechanical pencil C

—

—

—

—

Important tasks do not influence synthetic evaluation

Table 3.6   Important Tasks to Influence Synthetic Evaluation Regarding UX

Explanatory variable

Response variable

Task 1

Task 2

Task 3

Task 4

Synthetic evaluation

of UX

Picking up mechanical pencil

Holding mechanical pencil

Clicking mechanical pencil

Writing

Mechanical pencil A

—

✓

—

—

Mechanical pencil B

—

—

✓

✓

Mechanical pencil C

✓

—

—

—

FCA is very useful in the case of a lot of parameters such as attributes or evaluation items in a matrix, because it makes them clarify the relationships between them. Although the relationship of the parameters of mechanical pencils is not complicated, FCA is useful and easy for designers, engineers and planners, and so FCA is introduced using this example in this section.

  • The questionnaire data was changed into binary data

The average of user requirements and UX of mechanical pencils A, B and C were changed into binary data. If the usability or UX average is higher than the usability average (2.99) and UX average (2.23) for each total average, the average is 1 (Tables 3.7 and 3.8). If lower, the average is 0.

  • Making Hasse diagrams

Table 3.7   Binary Data for Usability

Task 1

Task 2

Task 3

Task 4

Synthetic evaluation of user requirements

Picking up mechanical pencil

Holding mechanical pencil

Clicking mechanical pencil

Writing

A

1

1

0

0

1

B

1

0

0

0

0

C

1

0

1

1

1

Table 3.8   Binary Data of UX

The average of UX

Task 1

Task 2

Task 3

Task 4

Synthetic

evaluation of user requirements

Picking up mechanical pencil

Holding mechanical pencil

Clicking mechanical pencil

Writing

AV

AV

AV

AV

AV

A

1

1

0

1

0

B

1

1

0

0

0

C

1

0

1

1

1

FCA shows a Hasse diagram using the binary data of usability and UX (Figures 3.6 and 3.7).

  • Interpreting the Hasse diagram

Figure 3.6   The usability output of FCA.

Figure 3.7   The UX output of FCA.

Each mechanical pen is connected with its evaluation item through lines from the top point in the Hasse diagram. An arrow is added to understand the relationship between the mechanical pencils and the evaluation items. Users can understand the relationship according to the arrows from the top point to the mechanical pencil. The evaluation items located in the upper position in the Hasse diagram are important and shared with many mechanical pencils.

3.4  REM (Hierarchical Requirements Extraction Method) (Yamaoka 2013)

3.4.1  Background and Purpose

After a usability specialist has observed products or systems, they only extract problems of usability and improve them. However, they don't usually grasp the root cause and final purpose. Grasping the root cause and final purpose of products and systems can give an ideal and essential understanding of them for the usability specialist.

REM is a method to extract user requirements by root cause and final purpose based on problems of products or systems. The relationship between results and cause may require the root cause of products and systems, while the relationship between purpose and means may require the final purpose.

3.4.2  Proposed Method

The procedure of REM is as follows (Figure 3.8).

Figure 3.8   The structure of REM.

How to obtain the final purpose

  1. Problems are extracted based on observation, protocol analysis, check list, questionnaire and so on.
  2. A problem is selected and solutions are produced based on the problem.

In the case of a heavy camera as the problem, a light camera is the solution.

  1. A purpose is needed from the perspective of the relationship between purpose and means. In short, the purpose is realized using the means.

For the example above, no fatigue to use the camera is the purpose required based on the means of a light camera.

  1. Each purpose is required to repeatedly raise the saturation state from the perspective of the relationship between purpose and means.
  2. The final purpose is produced when the purpose cannot be abstracted.

New user requirements and UX are created based on the redefined final purpose. For the above-mentioned example, the final purpose is to realize comfortable operation. As one example, a new camera with all voice instruction is produced based on the idea of comfortable operation.

How to obtain root cause

  1. As the problem is the result, a cause is needed from the perspective of the relationship between the result and cause.

For the above example, the problem is the heavy camera and so the cause seems to be to have a lot of functions not used in the camera.

  1. Each cause is required repeatedly up to the saturation state from the perspective of the relationship between the result and cause.
  2. The root cause is produced when the cause cannot be abstracted.

For the example above, the root cause seems to be technicism.

The second hierarchy level of the final purpose is concrete user requirements, and the second hierarchy level of the root cause is the concrete cause of the problem. The opposite concepts of the concrete causes of the problem show the user requirements.

As REM can extract the final purpose and root cause of products, systems and so on, the user requirements and UX can be produced.

3.4.3  Observation

Before doing REM, observation is required to obtain the problems. Although the problems are also obtained by usability-UX task analysis, easy observation is introduced. The problems are extracted easily from the viewpoint of the five aspects of HMI (human–machine interface). The total 15 check items of the five aspects of HMI can easily search for problems (Table 3.9).

Table 3.9   Five Aspects of HMI and 15 Items

Five aspects of HMI (human machine interface)

Search problems using the following items

1.

Physical aspect

  • Check user's posture
  • Check operational direction and strength of the controls
  • Check fit between the controls and the user's body

2.

Information aspect

  • Check user's mental model
  • Check easiness to understand
  • Check easiness to see

3.

Temporal aspect

  • Check working time
  • Check recess
  • Check machine response time

4.

Environmental aspect

  • Check air conditioning
  • Check lighting
  • Check noise and vibration

5.

Organizational aspect

  • Check organization's policy
  • Check information sharing among members
  • Check motivation of members

3.5  Example of REM Application

An example of a desk lamp in a hotel and a cafe shop using REM is shown.

  1. A desk lamp in a hotel room (Figure 3.9)

Figure 3.9   A desk lamp as an example of REM.

As a desk lamp inside causes glare, it's very hard for customers to read books or PC screens. Although the hotel is a business hotel next to a railway station, desk lamps used in luxury hotels are usually placed on a desk. After using REM, the final purpose is defined as “Providing a comfortable environment in the room.” A new idea “Barrier-free design for everybody” is created based on the final purpose and root cause.

  1. Cafe shop (Figure 3.10)

Figure 3.10   A cafe as an example of REM.

A new idea “Providing a familiar user experience and healing in a cafe” is proposed as the final purpose to solve “Not having customers in a café.” Finally, “Easy access to the cafe, and forming a familiar interior of healing with aroma, sound, etc.” is created.

3.6  UX System Diagram

3.6.1  Background

UX system diagrams can create UX and feelings based on the four attributes of product, story, feeling and sense by UX. UX becomes an important factor to construct various designs. It is difficult to create UX based on human intuition because of its ambiguity. If designers and engineers depend on intuition to design, they require a lot of knowledge, intelligence and experience. However, they can construct UX using the UX system diagram as a frame of thinking even if they don't have a lot of knowledge, intelligence and experience.

3.6.2  Proposed Method

This method creates a new UX using a combination of the following four factors.

  1. Three attributes of the product: useful, usable, desirable (Null and Cherry 1998)
  2. Story: newest story, real story, historical story, fictional story
  3. Feeling: lovely, admired, joyful, interesting, impressed, surprised, expected, comfortable, satisfied
  4. Sense from UX: sense from UX is produced by user experience (UX). There are seven kinds of sense: extraordinary sense, sense of usability, sense from the five senses, sense from obtaining, sense of admiration, sense after doing tasks, sense of familiarity (Table 3.10).

Table 3.10   Definition of Senses by UX

Senses by UX (senses produced by user experience (UX))

Sense

Definition

Extraordinary sense

Sense from travelling and going to a concert

Sense of usability

Sense from usability such as Web services and IC cards

Sense from five senses

Sense from five senses such as watching a 3D movie and smelling perfume

Sense from obtaining something

Sense from obtaining useful information and accepting presents

Sense of admiration

Sense evoked by admiration such as big-name brand products and favorite artist

Sense after doing a task

Sense of accomplishment, fulfillment and unity such as completing a project

Sense of familiarity

Sense from familiarity such as attachment to an old house or old watch

Figures 3.11 and 3.12 show the relationship between the three attributes of product, story and feeling and sense by UX. If the relationship between the two keywords is closely related, a line is drawn between the two keywords such as newest story and surprised and so on.

Figure 3.11   UX system diagram in useful and usable aspects of product or systems.

Figure 3.12   UX system diagram of desirable aspects of product or systems.

How to use the UX system diagram

  1. Making a story using the UX system diagram
  2. Suitable keywords are selected from the UX system diagram
  3. As selected keywords are connected and lines drawn, the story and UX are decided.

3.7  Example of UX System Diagram Application

Two examples:

  1. Latest medical equipment introduced into a hospital

When a hospital introduces latest medical equipment, the patient or people planned to be hospitalized have expectations on their sense of its administration.

The items of “Useful, Usable,” “Newest story,” “expected” and “Sense of admiration” are connected as one story (Figure 3.13). Each item selected shows concrete content as below:

  1. “Useful, Usable”------ “Newest story”------ “expected”------“Sense of admiration”
  2. “Useful, Usable”: latest medical equipment
  3. “Newest story”: the hospital introduces the latest medical equipment
  4. “expected”: patients or people planned to be hospitalized have expectations
  5. “Sense of admiration”: a sense of administration
    1. A fictional Cinderella Castle constructed

Figure 3.13   Example 1: Newest medical equipment introduced in hospital.

If a fictional Cinderella Castle in an amusement park is constructed, users enjoy and are moved from the perspective of having a dream and extraordinary sense (Figure 3.14).

  • “Desirable”------“Fictional story”------“joyful”------“Extraordinary sense”
  • “Desirable”: Cinderella Castle
  • “Fictional story”: a fictional Cinderella Castle was constructed
  • “joyful”: users enjoy from the perspective of having a dream
  • “Extraordinary sense”: users enjoy from the perspective of extraordinary sense

Figure 3.14   Example 2: A fictional Cinderella Castle constructed.

The UX system diagram can create a UX structure and decide a design plan using the three attributes of product, story, feeling and sense from the UX.

3.8  Conclusion

The three methods for usability and UX can show how to obtain user requirements and UX. Designers, engineers and planners as beginners of collecting user requirements especially can obtain them using the three methods without intuition.

Usability-UX task analysis can collect user requirements and UX efficiently and systematically. REM can also extract user requirements by root cause and final purpose based on the problems of products or systems. The problems can be found by usability-UX task analysis or observation. UX system diagrams can create UX and feelings based on the four attributes of product, story, feeling and sense from the UX. The relationship between the three methods is shown in Figure 3.15.

Figure 3.15   The relationship of the three methods.

References

Roberta. L. Null , Kenneth F. Cherry , 1998, Universal Design, 116. Belmont: Professional Publications, Inc.
Toshi. Yamaoka , 2012, A proposal of usability task analysis for user requirements and evaluation, in 4th International Conference on Applied Human Factors and Ergonomics (AHFE) Conference Proceedings, 7116–7122.
Toshiki. Yamaoka , 2013, Evaluating user interface design using hierarchical requirements extraction method (REM), in HCI International 2013, Conference Proceedings, 137–142.
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