In UX design, efficiency refers to the ability to intelligently help users accomplish their goals while minimizing the waste in time, energy, cost. The good thing is this can easily be measured and optimized, but it’s also worth noting that there are often other qualitative aspects of UX that is harder to measure and are equally critical, such as clarity, comprehension, and perceptions. i.e. faster is not always better.
Vogt, JD. “Defining Principles to Drive Design Decisions – Salesforce UX – Medium.” Medium. February 04, 2016. Accessed October 16, 2017. https://medium.com/salesforce-ux/defining-principles-to-drive-design-decisions-b647b68fb057.
Example from original source
Example not cited by original source
Google’s Answer Box tells you what you need to know without you having to click on the web pages. An example here.
Example from real life
It’s common in Japan to order your food through a machine before you sit down. This saves time for customers, waiters and overall make a quick eat-and-go experience very efficient.
Efficiency is one the key factors to amazing UX. If something is not intuitive or is a complicated process your product will most likely fail. I like how you mentioned that efficiency can be quantified. This is important to keep in mind. You need to qualitatively measure this principle to speak to the KPI it effects back to your company. I love the machine you order from in Japan. This can be measured by how fast you get your food compared to ordering it from a waiter. Here is an example of an efficient way to get a salad. Let me know what you think of this concept.
https://www.youtube.com/watch?v=XdhZnP10n6A
The food ordering machine is such a great example of the concept of efficiency. The machine itself appears well designed and it is clear that the restaurants have put a lot of consideration into creating an efficient experience for both the customers and the staff working there which would overall make the experience a positive one rather than having lengthy wait times or miscommunications. An example I can think of that is similar is the Starbucks mobile order app which allows customers to order their items online, prepay, and then pick them up already made without having to wait in any lines. This allows customers to get what they need and want quickly and efficiently without having to spend time waiting in the actual store itself; a very attractive feature to people who are busy or have a very limited amount of time to accomplish their errands or tasks. https://www.starbucks.com/coffeehouse/mobile-order