+2 votes
asked in Product Design by (14 points) | 948 views

4 Answers

+3 votes

Let's clarify the question first. 

Is it a particular retail store or a chain of a store: Lets says a particular local grocery store.

Does the store have self-checkout: Yes

Is the wait time long for self-checkout or counter checkout: Both

When do users complain the most (time?): Evening 

Identify Personas 

* Users with cash: carrying 5 items or less OR 5 items or more

* Users with card: carrying 5 items or less OR 5 items or more

Report Needs

Enhance the user experience by reducing the complaint from users (considering we are providing the solution for the users mentioned in the above category) about long queues during checkout 

SolutionImpact to usersComplexityCost to business
Provide estimate wait time so that the user has the clear info and decide if they want to come back againHighLow (store already has the data based on the history)Medium
Provide snacks (something from the in-house bakery) to enhance their user experience Medium (There is still a wait but the users will be happy with the free snacks)LowLow
Staff people who would go to the users waiting in the line with the credit card and charge them via the card processor HighLow (the tech already exists)High (more staff + cost of the card processor)
Improve checkout process by giving cashless experience - tie-up with google wallet / paypal HighLowMedium
Introduce membership service - allow users to drop off the items in their cart at the counter and select a delivery time; the store staff will charge their card registered in the system (offline) and deliver the items at the time specified by the userHighHigh (need to build a system for membership)Medium
Build an app for online grocery shopping and delivery HighHighHigh

Based on above as a short term solution, I would go with 1 , 2 & 4

For Long term 4 & 5 could be combined for a better user experience 

answered by (73 points)
Great answer. Enjoyed reading how well you described the ideas and evaluated your options. This will impress the interviewer.
+1 vote

Location and context  - retail store


let’s assume grocery store,

 let’s assume one specific grocery store branch,

 let’s assume it’s not a walkup grocery store, most customers drive in - only the grocery store around (we can’t send customers to other errands and then let them pick their stuff up later), 

let’s assume that if customer is there, shopping - they want to use some of the ingredients ASAP

Deeper look at the UX 


Complaints about long queues - how long? when? Long queue actually means long wait time to get through the register. 

That journey includes - 

 -  shop, look for a register with perceived shortest wait time,  stand in line, wait for turn, put items on belt, pay, pack, get out

What is the standard acceptable wait time at a grocery store and how much over that are we?

Long is a perceived, assuming customers are greedy for their time, so as a target we need to provide what’s acceptable industry wise/psychologically as a target, unless our store’s competitive advantage is shortest  (or no?) wait times. 

So the goal is reduce queue time to what is common in other, higher satisfaction stores if we part of chain, or to what the industry standard is.

Deeper look at the problem


Long queues are an operational problem- 

(people X items)/ staffed register = throughput -> customers checked out per/minute  —> the faster, the shorter the queue wait time

—we are assuming that cashiers operate at highest performance when behind register

—we assume that customers can easily operate the self checkout registers

—we assume here that people stand in the right line

this implies solutions are either 

reducing the number of people that need to go through the register 

reducing the number of items customers check out

reducing the amount of time it takes to take a single customer through checkout -  wrt to the journey

increasing the number of (staffed) registers

Need to take into account existing channels/shopping UX methods the store currently employs


  1. online shopping and delivery? - already exists? how is it going?
  2. online shopping and store pick up ? - already exists  ? how is it going?
  3. shop in store - deliver home (check out handled async)? already exists ? how is it going? - this tho might not work for someone who already came to the store, because it creates an unnecessary delay between picking the items and actually using them.

———^ improving or introducing the above can be part of the solution ^—— the longer term one

———v below is where the problem is felt by customers this is where most short term solutions come from v—————

4. shop in store - check out through self checkout (how) 

4.1 self checkout register?

short term - Can customers easily use them, are they efficient and fast enough ? if not, assign staff to help customers through until customers learn

long term - buy more self checkout stands - if the strategy is still to bring people into stores

4.2 mobile app checkout?

long term - does one exists today? if not this is a long term solution ?  

medium erm - if exists, but not used, usability studies are required to understand why not used 

assuming these don’t exists—all long term

4.3 dedicated device, just scan and leave   long term option if preferred over mobile phone checkout/no digital strategy in sight

4.4 no checkout needed, no device -just pick and go? - long term, depends on store digital strategy and value proposition, most expensive option

5.0 shop in store - checkout at register with cashier

short term solutions will come from operational changes in store - 

5.0.1 -  is there any phase in the customer journey that could be addressed? look for a register with perceived shortest wait time,  put items on belt, pay, pack 

5.1  are customers standing in the right line? analyze baskets going through the register, if there are small ones between large ones, maybe we should just have someone guide customers to right register  — measure impact on satisfaction

5.2 segment customers into small/large basket - are the complaints coming from either group? are small ones  - we could adjust the small basket/large basket register ratios to fit the demographic according to time of day and majority of shopping times  - measure impact on satisfaction 

5.3 consolidate lines and create a single queue for a fast checkout register pool - instead of having individual lines for each - this also has a psychological effect as the overall queues appears to move faster - measure impact on satisfaction 

In order to reduce queue length  and improve customer experience during checkout, the short term strategy will be to address operational aspects of the registers and their staffing, with an understanding of the type of customers/shopping baskets that need the most attention - with each improvement (we will start with those that don’t require more staff, just different ops) - we will measure the improvement in performance and satisfaction and stop once we get to the defined performance goal.

For a long term strategy, depending on what channels already exist, we will focus on reducing the number of customers who need to be checked out individually -  in accordance with the grocery store or chain’s digital and operational strategy. However, that should be done not as part of solving the current problem of  long queueing, but as part of a larger operational strategy and should take into account the cost/benefit of each solution and it’s alignment with overall company goal (i.e. get more online purchases, get more customers into our stores etc, increase home delveries..)


answered by (23 points)
0 votes

Drilling down the problem statement of queue, why queue happens? The answer would be very simple! It's because demand is very high(items that need to be billed) and supply(POS machines) are limited. So the probable solution could be : 

1. The store would need more POS machines 

  • Either stationary or mobile, POS machines will consume more space, human resource and financial burden

2. What if we enable each customer to self checkout

  • Build a platform(preferably an app) that has in-build POS machine
  • Once someone scan the barcode, it should give all the latest offers on that product
  • The customer pays online via net banking or wallets and an e-bill is generated
  • The customer can easily checkout without any queue 

3. Depending on the proportion of digital vs non-digital payment users,  solving issues for digital users(or any one set) can lead to decrease in overall queue.

answered by (13 points)
Hi Rish,
I suggest you first ask more clarifying questions such as when the queue exists. Is it in certain hours or all the time? Is it seasonal, recent, or ongoing? Once you have a clear understanding of the problem, you can brainstorm a few solutions. Make sure that after brainstorming is done, you evaluate your solutions and compare them against each other via some criteria such as the one done by garima above. And in the end, always always give a quick summary of how you derived your solution.
0 votes

Clarifying Questions:

What type of retail store? Phone retailer

How many checkout stations are currently there? 2

Are there any self checkout stations? No

Do they have an online store? No

Identifying the Users/ Observations:

Ages 18 - 45 (most likely to shop online in order to avoid long queues, if retailer had an online store)

Ages 45+ (most likely to shop in store to physically feel and test the products before buying)

User needs:

- Easier and faster way to checkout in order to avoid long queues

Short Term Solutions:

1. Hire additional checkout personnels: 

          - Benefit: Decrease long queues 

          - Tradeoffs: Increasing hiring cost 

2. Adding self checkout stations:

         - Benefit: Decrease long queues, Cost efficient in the long run

         - Tradeoffs: Installation costs, May deter less tech savvy users (45+)

Long Term Solutions:

3. Creating an online store (web/mobile) for users to review and buy products:

              - Benefits: Decrease long queues, Create another avenue for users to buy products (esp. for users 18-45) 

              - Tradeoffs: Development & maintenance cost for retailer, shipping costs for users

4. Create a self checkout mobile app for users to scan and checkout products using mobile payment (Apple pay/Google Pay) or CC in-store:

             - Benefits: Decrease long queues, cost effective in the long run

             - Tradeoffs: Development & Maintenance costs, may alienate less tech savvy customers

Best Solutions:

Short Term: 

#2 - Adding self checkout stations

Long Term:

Combination of #3 & #4 - Creating an online store with self in store checkout as a feature

answered by

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