Grocery Self Checkout Interface
Human Factors and UX Evaluation
The Self Checkout Experience
Self-check-out systems allow customers to scan, bag, and pay for their items without a cash register employee.
The primary perceived benefits of the self-checkout kiosks are time efficiency and a sense of control throughout the experience.
The Problem
While grocery self-checkout systems are aimed to facilitate the purchasing process, many users encounter poor experiences with the technology.
Customers that aim to checkout independently and quickly often experience technical issues and confusion, resulting in extended performance times and employee assistance, defeating the purpose of the self-checkout experience.
The Goal
The goal of this evaluation was to conduct and document a human factors evaluation on the grocery self-checkout experience.
The evaluation was completed for a course in my Master’s program: Advanced Human Factors.
Timeline
Feb 2022 - May 2022
Team
Solo
The Process
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1. Emphasize.
| User Interviews
| Focus Groups
| Surveys
| Market Research
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2. Define.
| Problem Statements
| Functional Requirements
| Personas
| Empathy Map
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3. Ideate.
| Brainstorming
| Sketching
| Wireframing
| Exploration
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4. Prototype.
The project did not reach prototype phase.
“It’s embarrassing being yelled at by a machine and there’s nothing to do.”
User Interviews and Focus Groups
I reached out to friends and family asking if they were willing to answer some questions about their self-checkout experience. 12 people volunteered for direct interviews, and many others were open to facilitating a discussion in a group chat.
The goal of the user interviews was to gather insight into their first-hand experiences and opinions of the self check out systems. I was interested in understanding their motivations, frustrations, annoyances, and what other factors impacted their experience.
Key Motivators
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Number of items
The most-reported motivation from my interview subjects was purchasing a limited amount of items (less than 15).
People feel like it is unnecessary to ask for help to purchase a small number of groceries.
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Time efficiency
Many subjects found the self-checkout system to be faster than other traditional methods.
They preferred the rate at which the lines move and how quick they are able to accomplish the scan-and-go interaction
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Full control of experience
Customers like the experience of being in control and doing things on their own time and agenda.
Some liked having the privacy of completing the check out alone, while others said they felt a sense of accomplishment doing the work
What People Are Saying
“I never (almost never) buy more than 15 items as I live in a large city (NYC) and don't have room to store a bunch of items. I'm usually, if not always, faster than the checkout person”
— Anonymous Subject (Customer)
“Often faster. Even if it’s not, I don’t like standing around doing nothing waiting for someone else to finish their job.”
— Anonymous Subject (Customer)
Key Problems
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Technical errors
The majority of volunteers expressed their distaste for machine errors (e.g. bagging area; weight scale errors; produce, etc).
Machine errors cause confusion, embarrassment, frustration, and impatience.
In most cases, machine errors require employee intervention to address or bypass the error.
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Scanning produce
Customers do not like scanning produce because it requires the additional steps of entering the appropriate code, searching the item by name, searching the item by photo, and then weighing or entering the number of items.
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Employee interaction
Similar to technical errors, many customers did not like interacting with an employee.
Whether it was for addressing a technical issue, scanning an ID, entering a code, etc, customers felt like it defeated the purpose of self-checkout.
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Customer induced errors
Employees are annoyed when the root of the issue is the customer failing to follow the instructions.
What People Are Saying
“If you take your bags off of the scale, wait for me to clear it. You cannot take bags off in the middle of the transaction without the computer stopping you from scanning anything else. And don’t argue.”
— Anonymous Subject (Employee)
“ [I dislike] the embarrassment of waiting for an employee when you need help/make a mistake.”
— Anonymous Subject (Customer)
Survey
A survey was distributed to friends, family, neighborhood Facebook groups, and Reddit forums.
A total of 501 people completed the survey.
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How often do you use the self-checkout machine at the grocery store?
What motivates you to use the self-checkout machine?
What do you dislike about the self-checkout machine?
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“If you have any additional comments or would like to express anything about your experience with the self checkout systems, please enter below.”
Key Results
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Customers frequently use self checkout.
51% of surveyors reported using the self checkout machine always or most of the time.
| Of those who answered always, 75% fell in the ages between 18 and 44 years old.
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Time efficiency is a primary motivator.
68% of surveyors said time efficiency was a primary motivator.
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“ Often faster. Even if it’s not, I don’t like standing around doing nothing waiting for someone else to finish their job.”
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Customers want to avoid other human interaction.
49% of customers said they like self-checkouts because they can avoid interacting with others and keep to themselves throughout the experience.
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Customers like full control of the experience.
43% of customers enjoy the feeling of having full control of the grocery experience.
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“ [ I like to ] have cashier experience and like to do things "my way".
A poor experience
“I hate placing the item in the bagging area after I have already done so.”
— Anonymous Surveyor (Customer)
“It’s very annoying when they don’t let you scan another item until you put the previous one in the bagging area.”
— Anonymous Surveyor (Customer)
“Don’t mind doing the self serve but not enough room to bag large cart purchases and always have to wait on employees to correct an error or restart the process.
— Anonymous Surveyor (Customer)
Too many errors
“ Sometimes they don’t work as they should.”
| 64%
of surveyors said they dislike the self checkout machine because it causes too many errors.
“It seems that there are a lot of rules for how to use the self-checkout that aren't made known to users - how the weight sensors work and knowing to put an item in the bag before picking up the next item to scan; weird time limits for how long it will let you set up your own reusable bags in the bagging area before throwing an error.”
Identifying Key Problems
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| Complicated User Interface
Customers are not trained like employed cashiers are.
As a result, customers are faced with complicated interface components and language, increasing the likelihood of error.
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| Scanning Produce
Customers hate the additional steps it takes to scan, check, and bag produce.
In many cases, users are required to find the produce code before purchasing.
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| Bagging Errors
Customers often face bagging errors, especially when using their own bag or placing items in their cart to make more space.
The system typically pauses and requires employee assistance.
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| Confusing System Feedback
System errors rarely communicate the issue and how to address them.
System errors also tend to freeze the machine, requiring additional assistance from an employee.
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| Lack of System Control
The machine fails to give the user control of its settings.
For example, users want to bypass certain errors or toggle the audio level. Some customers have expressed embarrassment from the machine demanding the customer to follow specific instructions.
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| Extended Wait Time
Customers felt like the additional time required to wait for employee assistance defeated the purpose of the self-checkout experience.
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| Too Many Technical Issues
The system originally designed to expedite the self-checkout process tends to freeze or lag due to user or system errors.
The technical issues also fail to communicate the problem in a language that the normal customer would understand.
Personas
2 personas were created to serve as a fictional representations of the customer and the employee.
Empathy Map
An empathy was created to represent the users and their attitudes and behaviors.
Exploring Solutions
Interface Solutions
A number of the issues expressed by users can be addressed by exploring the design of the system interface. Mid-level wireframes were designed to showcase design improvements.
Business Solutions
There are also business-related solutions that can be introduced to mitigate some of the issues experienced at the self-checkout lane.
Establishing UI Requirements
Requirements for the interface redesign were established to improve the self checkout experience.
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Users must understand how to use the machine immediately.
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Users must be able to toggle and control the system settings as they see fit best.
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Users find it difficult to understand the root of system errors and how to address them.
The system must provide feedback with familiar language, allowing users to easily understand the situation.
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Currently, the interface replicates the trained cashier experience. However, most customers are untrained. This leads to many user and system errors.
Wireframing Solutions
The goal of the new user interface (UI) is to provide an easy-to-understand design for users. Current self checkout systems replicate the interface for what an employed cashier uses.
The new interface design is aimed to give users a simple model.
Business Solution
Produce Bar Code Model
If a produce item does not have a barcode sticker, customers are required to enter the item code (which many fail to know immediately).
When purchasing raw meat, deli meat, or seafood, customers receive their items with a premade label. The label has the item description, weight, price, and barcode.
Customers should have a similar opportunity for purchasing produce. A ticketed machine should be available for customers to create a label with a barcode nearby.
Future Directions and Limitations
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The next appropriate step of the design process would be to perform formative evaluations of my design solutions.
Given the time and resources, it would be imperative to transition my designs into usable prototypes to conduct performative and usability analyses. Performative and usability analyses would provide quantitative data to better understand how the users’ experiences are affected.
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A popular complaint from customers was the poor experience purchasing alcohol via self-checkout.
However, there are laws and ordinances in place (vary by local and state governments) that enforce these rules. Understandably, it is the business’ best decision to prevent underage purchases.
The best possible solution explored was providing a feature that gives employees a heads up notification about a future alcohol purchase, streamlining the ID verification process.
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Self checkouts are vulnerable to theft. However, employees have expressed it is an issue beyond their control
Although the likelihood of theft is greater with a machine than a physical person, addressing theft was not a primary problem nor goal in this design evaluation.