Costco Mobile App

A Heuristic Evaluation uncovered high priority usability problems in the native iOS mobile application


Making it easy and efficient to search and sign home rentals based on the user's preferences without being scammed



Why I completely redesigned my portfolio website - Usability in Web Design.

Neuel Sam

1 Min Read, 15 July 2020

Problem Space

Costco Mobile App encompasses all Costco services available on the website. Customers can buy products and memberships, check nearby warehouses, and process returns. I conducted a heuristic evaluation in order to identify usability issues in the application.

Once Usability issues are identified, potential solutions are implemented and the prototype is re-evaluated against the same heuristics to ensure that the usability issue no longer exists.


  • Must follow existing Costco Application design.

  • Fonts can be free open source ones instead of paid.


Redesigned Screens after Heuristic Evaluation: Download PDF

Design Handbook: Download PDF

User Task

Browse groceries to find Croutons and buy them.

Heuristic Evaluation

A method to find usability problems in a user interface design. We examine the interface and judge it’s compliance with recognized usability principles using a small set of evaluators.

Heuristic Evaluation Rating Method

Not a usability problem at all
 Fix only if extra time is available
Low priority usability problem
3  High priority usability problem
Usability catastrophe

Help Users Recognize, Diagnose and Recover From Errors

  • The error message should be written in plain language

  • Messages should precisely indicate the problem

  • Messages should constructively suggest a solution

User Control and Freedom

  • Users often choose options by mistake

  • Users need an exit strategy to leave the unwanted state

  • There should be freedom to undo any accidental actions

My Role

Heuristic Evaluator



1 Week

Usability Heuristics Evaluated

Aesthetic and Minimalist Design

  • Dialogue shouldn’t contain irrelevant information

  • Extra information competes with relevant information

  • Prioritize the content that supports the user’s goal

Consistency and Standards

  • Users wondering the meaning of symbols/actions/words 

  • Follow platform conventions

  • This helps in reducing learning curve and eliminates confusion

Visibility of System Status

  • Communication and transparency

  • Users should know what’s happening in the system

  • Prioritize content that supports the user’s goal

Identified Usability Issues and Ratings

Help Users Recognize, Diagnose and Recover From Errors

Sign In Error

The cause of the error is not specified, so users are left guessing what went wrong

Specify what went wrong and highlight respective fields with

Rating: 1 (Fix only if extra time is available)

User Control and Freedom

Back Button

This back button does not navigate through the system hierarchy, so users cannot retrace their steps.


The back button should respect information architecture.

Rating2​ (Low priority usability problem)

Aesthetic and Minimalist Design

Cluttered Info

Too much irrelevant information is presented, diminishing visibility and making the task difficult to complete.


Take out information not relevant and provide a hierarchy of content information.

Rating: 3 (High priority usability problem)

Consistency and Standards

Is It Clickable?

A lack of consistency in terms of what is clickable and what is not, leaves the user confused and unsure.


Implement consistent button format to show active and inactive states

Rating: 2 (Low priority usability problem)

Visibility of System Status

Checkout feedback

No feedback after clicking Checkout than a slight color change, causing the user to wonder if the system is still responsive


Display what is happening in the back end to the user

Rating: 4 (Usability catastrophe)

Executive Summary

Overall Usability Rating

Users are able to do the main task but with confusion and frustration. Overall,  the app was given a 2.5 on the usability scale.

Recommendations Implemented

Prototype Link: Click Here



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Discover, define, develop and deliver

Hello, I am Neuel Sam. A systems design engineer crafting products based on human-centered design. Welcome to my portfolio.



Why I completely redesigned my portfolio website - Usability in Web Design.

Neuel Sam

1 Min Read, 15 July 2020

Other Projects



Why I completely redesigned my portfolio website - Usability in Web Design.

Neuel Sam

1 Min Read, 15 July 2020