Vladyslav Gorbunov gorbuvla(ac)fel.cvut.cz CTU in Prague A4B39TUR

Viber usability testing

Application description 1 ​ User description 1 ​ Usability inspection methods 2 ​ Cognitive Walkthrough 2 ​ Heuristic Evaluation 2 ​ Use cases and motivation 3 ​ Registration 3 ​ Adding new contact 3 ​ Sending message to Viber user 3 ​ Adding participants to a group chat 3 ​ Chat background customisation 3 ​ Evaluation 4 ​ Use case 1. Registration and application setup. 4 ​ Use case 2. Adding new contact. 6 ​ Use case 3. Sending messages. 7 ​ Use case 4. Adding participants to a group chat. 8 ​ Use case 5. Chat background customization. 10 ​ Discovered issues 12 ​ Conclusion 13 ​ References 13 ​

Application description Purpose of this document is to test popular application for instant messaging and free instant calls Viber. Viber has already gone through some major updates and remains popular thanks to its simplicity, fast response and reliability. Viber allows users to sync with their contact list and automatically detect contacts whose phone number was registered in Viber service. Viber also supports public chats, sending documents, video calls, calls and messaging outside Viber service. Application is available for majority operating systems, but historically was orientated on mobile platforms and authorisation on a desktop device requires confirmation via interface of pre-installed application on a smartphone.

User description The target audience consists of people who use mobile applications in a daily routine and are looking for fast and cheap way of sending text messages or performing instant calls. Target audience is supposed to be familiar with application installation routine, basic navigation in a particular mobile device, knowledge of using built in keyboard as an input interface is also required. Application will be tested under Android 6.0 operating system, application version 5.8.0.1736.

1 Usability inspection methods

Cognitive Walkthrough The cognitive walkthrough is a usability inspection method used to identify usability issues in interactive systems, focusing on how easy it is for new users to accomplish tasks with the system. The only precondition for using this method is the fact, that responsible evaluator is familiar with tested product and knows exactly what to do in each step of a particular use case to accomplish given task. Cognitive walkthrough is task-specific and in order to use this method we need to proceed with predefined questions for each use case.

Those are: Q0: What does the user want to achieve? (At the beginning of the test)

Q1: Will the correct action(s) be evident to the users? Q2: Will the user connect label of an action with their goals? Q3: Will the user receive a sensible feedback? The output of this method consists of a list of findings represented in form of answers on questions mentioned above.

Heuristic Evaluation Heuristic evaluation is a usability inspection method that specifically involves evaluators examining the interface. Each appointed expert goes through provided interface several times and judges compliance of various parts of the interface with generally recognised usability principles(the “heuristics”). We will assume Nielsen’s heuristics, which are as follows (as published in Nielsen's book Usability Engineering):

1. Visibility of system status 2. Match between system and the real world 3. User control and freedom 4. Consistency and standards 5. Error prevention 6. Recognition rather than recall 7. Flexibility and efficiency of use 8. Aesthetic and minimalist design 9. Help users recognise, diagnose, and recover from errors 10. Help and documentation The output of the method is a list of usability problems each referencing infringed heuristic.

2 Use cases and motivation

Registration Registration is an important step in application usage cycle and it is a first step in user decision whether he/she is satisfied with provided interface. It is important to provide user with help and step-by-step instruction to fulfil the registration process. Poor registration interface may deter potential users. Here we will go through the process of application setup. Expected issues: here I expect only cosmetic issues, feedback may also be poor. ​

Adding new contact With a registration process complete this is another significant step before user can make use of major part of application provided services. This process may be sometimes confusing, that is why apparent interface is important in this phase either. In this use case we will add new contact using mobile phone number and a QR code. Expected issue: badly designed feedback information. ​

Sending message to Viber user This is where the main functionality of tested application is grounded. Since it might be the most frequent procedure user will go through, fulfilment of common design principles is obligatory for user task accomplishment. We will try to send text and media messages here. Expected issues: visibility of system status, match with the real world. ​

Adding participants to a group chat User may also take advantage of group conversations. With the evolution of social communication services this became rather standard than option. While some parts of the application might be responsive and straightforward, badly designed interface may hide some of the functions user will never know about. Expected issues: not intuitive, user may not connect label of an action to a goal. ​

Chat background customisation Optional functionality is always good as long as target audience can make use of it. Sometimes it even defines why user sticks with offered software instead of considering competitions products. In this case application offers customisable background for chats which is supposed to make application usage more pleasant. Optional functionality may be a big benefit as long as it is obvious to use. In this use case we will walk through the process of changing chat background. Expected issues: poor feedback. ​ 3 Evaluation

Use case 1. Registration and application setup. We will use cognitive walkthrough there. Q0: User has installed Viber application and wants to complete registration. Steps to proceed: 1. Start registration process 2. Enter phone number 3. Verify phone number 4. Enter code

Step 1. Starting registration process.

Q1: Yes. Q2: Yes, action is labeled with “Continue” button. Q3: Yes, user will be redirected to next step.

Step 2. Entering phone number. After starting an app ​

Q1: Yes, it is a part of registration process. Q2: Yes, hint is displayed to help user. Q3: Yes, user will be prompted to verify supplied phone number.

Entering phone number Verifying phone number ​ 4 Step 3. Entering security code.

Q1: Yes. Q2: No, in later versions user receives a phone call and code is filled automatically. The call may however distract user. Q3: No, user is redirected to application homescreen without any notification about registration status.

Missed confirmation phone call Application Homescreen ​ ​ (registration is confirmed)

Summary: found issues are not crucial ones, since the user will probably go through the ​ process of registration only several times. Confirmation phone call may be distractive however. User is prompted to enter security code received by SMS and a phone call is received instead. In both cases whether user answers an autofill call or not, security code is submitted automatically, which is at certain point strange. User will also receive no status information after security code fill, homescreen did appear with no further information. Small toast message would be enough.

5 Use case 2. Adding new contact. Heuristic evaluation will be used since we have multiple ways achieving desired result, either by filling in a phone number or scanning a QR code.

List of findings: a) Badly designed hint. Hint in a QR scanner suggests opening a QR code from a “more” screen, which I happen to call drawer. Either way, there is no “more” menu in the settings. [ Help and Documentation ] ​ ​

Hint suggesting to open misterious Adding new contact using QR code “more” screen

Summary: this might be the most useless use case since I had not encountered any ​ significant usability problems. The hint description looks strange for me but it might be more understandable for majority of Viber users. Both adding methods using phone number and QR code are pretty intuitive and any user should proceed with this task well.

6 Use case 3. Sending messages. Since we will send multiple message types, heuristic evaluation might be the best way to inspect usability problems in this use case.

List of findings: a) Message status if receiver is off network. Message will not be indicated as “Delivered” or “Seen”, it will not show any status at all, which may be sometimes confusing. [ Visibility of System Status ] ​ ​ b) Additional message types are hided under “plus” button. Users might be more familiar with classic “clip” variant. [ Match between system and the real ​ world ] ​

Message status not ​ defined

“Plus” label ​ ​

Summary: Viber sends all data I use daily (texts, pictures, archives, etc). The argued ​ “plus” button is just a cosmetic issue which might not even be considered as violation of a particular heuristic. I must admit, that the “plus” fits better in overall Viber design than a “clip”. The “message status issue” need to be solved however.

7 Use case 4. Adding participants to a group chat. This use case has a clearly defined steps to achieve desired result, that is why we will use cognitive walkthrough usability inspection method.

Q0: User wants to start a group chat. Steps to proceed: 1. Add new chat. 2. Select “New group”. 3. Add participants and confirm.

Step 1. Adding new chat.

Q1: Yes. Q2: No, some users may not be used to Floating Action Button. Q3: Yes, list of available participants will be shown.

Homescreen ​

Step 2. Selecting new group.

Q1: Yes. Q2: Yes, label matches its function. Q3: Yes, redirection to the next step.

Selecting “New Group” ​

8 Step 3. Adding participants and confirming.

Q1: Yes. Q2: Yes, selecting items from ListView is a common in nowadays applications. Q3: Yes, after confirmation chat screen will appear.

Selecting participants Created group chat ​ ​ ​

Summary: this use case did not reveal any bad design implementation. Some users may ​ be unfamiliar with the Google Material Design Floating Action Button. It is not a big issue since majority of Android devices still run late versions of Android 4 and changes are about to come.

9 Use case 5. Chat background customization. There is only one way of achieving demanded result, usability errors will be inspected using cognitive walkthrough there.

Q0: User wants to change chat background image. Steps to proceed: 1. Reach settings menu 2. Chat background 3. Select picture

Step 1. Reaching settings menu.

Q1: Yes. Q2: Yes, toggle button is a common design principle. Q3: Yes, navigation drawer will show available settings list.

Homescreen Navigation Drawer Settings ​

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Step 2. Reaching chat background settings.

Q1: Yes. Q2: Yes, one of the settings item has same label. Q3: Yes, background settings will appear.

Background settings Step 3. Selecting picture.

Q1: Yes. Q2: Yes. Q3: No, some kind of preview is missing.

List of default backgrounds Settings with changed background ​

11 Summary: in my opinion relatively big issue was discovered here. After selecting new ​ background user will see no preview. In my particular case i always have to go back to some chat, check how the new layout (background and messages) look like and in case i do not like it I have to go to settings again and change the background.

Discovered issues: There I will list all the findings and rate them using Severity Ratings for Usability Problems by Jakob Nielsen.

● [ 0 ] I do not agree that this is a usability error at all. ● [ 1 ] Cosmetic problem only. ● [ 2 ] Minor usability problem. ● [ 3 ] Major usability problem. ● [ 4 ] Usability catastrophe.

a) Inconsistency between provided information and system actions. [ Use case 1 ] ​ ​ The phone call vs SMS problem. Verdict: 2. b) Providing information about registration status. [ Use case 1 ] ​ ​ This is a cosmetic problem which might be solved with a simple toast message “Registration success”. Verdict: 1. c) Poorly explained hint from [ Use case 2 ] ​ ​ Once again, this is just my point of view, but since it distracts me a little I consider this as a tiny usability problem. Verdict: 1. d) Message status. [ Use case 3 ] ​ ​ This is more significant issue but once again nothing that may scare potential user. I have experienced problem of uncertainty when message was not even marked as “Delivered” for days even though receiver was connected to a network (Viber application was not accessed directly). Verdict: 2. e) ImageButton with “plus” label. [ Use case 3 ] ​ ​ I consider this as a cosmetic issue, but not distracting one and since I have already mentioned that it might fit better in Viber UI than suggested “clip”, I will give it the lowest priority. Verdict: 0.

12 f) Floating Action Button. [ Use case 4 ] ​ ​ Although I have the latest version of Android for several months already, some Google Material Design guidelines are a bit confusing for me. As long as this is accepted as standard by Google for quite a period already, it is most likely that Floating Action Button will remain. Verdict: 0. g) The missing preview issue. [ Use case 5 ] ​ ​ This one is certainly an error. As a solution I consider a “preview” screen to provide user with approximate look of the background with some random text messages. Verdict: 3.

Conclusion: During this work I have tested Viber messenger for Android platform. I have encountered some usability issues which in most cases were application-specific features or reasonable deflections for achieving best experience from using Viber services. I have not tested features I never used and features I find useless, like public chats for example. Overall experience is quite good, Viber will probably remain one of the main resources for my communication with some people so far.

References: https://cent.felk.cvut.cz/predmety/Y39TUR/?page=home [ course page ] ​ https://en.wikipedia.org/wiki/Cognitive_walkthrough [ Cognitive Walkthrough ] ​ http://www.usabilitybok.org/cognitive-walkthrough [ Cognitive Walkthrough ] ​ http://www.usability.gov/how-to-and-tools/methods/heuristic-evaluation.html [ Heuristic Evaluation ] https://www.nngroup.com/articles/how-to-rate-the-severity-of-usability-problems [ Severity Rates ]

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