Part of a great user experience is ensuring that your users are able do what they care about doing, without having to be burdened by the thing they are using to do it.

This is true for just about any user experience, and has never been more relevant than today as users are constantly multi-tasking using several applications, sources, and/or devices at a given time. Be it an iPhone, game controller, email program, or golf club, they are all the same. Product and application designers must create interfaces that enable users to quickly and easily get into the activity they came to the product for, without having to be distracted by working too hard to use the product itself. The payoff for doing this well is that users and customers become endeared to experiences that allow an exceptional level of activity ‘flow’, and which help them do what they want to do because of the product design, not in spite of it.

But sometimes it’s hard to know if your design is clearing the way for users to let them do their thing - and not make them think too hard or create too many factors for them to manage. In this spirit I thought I’d provide an example of how I measure the ‘weight’ of an application user experience, that is, determine the degree to which users feel mentally and physically weighed down or distracted by interaction with a tool as opposed to the engagement in an activity (the goal). The more developers and designers can achieve ‘lightness’ in their user experience design, the more they can be sure that their user is able to focus on the good stuff the experience has to offer such as having fun, sharing, or getting stuff done.

Example: Asana v. Trello

Here is an example. Let’s say that you want to understand how ‘heavy’ or ‘light’ your app feels to use, and even measure it against a competitor to see how you stack up.

To demonstrate this I’ll compare two productivity/task management apps that offer similar activities, Asana and Trello. I’ll use a sample of one to keep the demonstration simple. I’ll also use the NASA-TLX scoring system that I described in an earlier blog post, which was designed to measure the workload, or demand, involved in using a given interface.

(Note lean ux’ers: because this scoring system is comprehensive and ready-to-use out of the box, I was able to complete this evaluation (n=1) in under two hours. Doing this experiment with a solid 5 users shouldn’t take more than one day. Not a bad trade for having some high value, competitive user feedback under your belt!)

Here are the steps to gauging the weight of a ux:

1. Determine your core activities, or tasks, you hope your users to achieve.

For my example I chose three simple activities that users commonly do using both the Asana and Trello apps: 1) create a new project & task, 2) share that task with someone else, and 3) close that task and project once it is complete.

2. After completing each activity, ask the user to rate the experience using the NASA-TLX ratings and scales.

This shouldn’t take more than 3-5 minutes per activity, and there are both paper and online versions available to use. Doing this step results in a simple and concrete number you can use to assess and compare the workload, or demand, the user feels while completing each activity (numbers=confidence!).

3. Once all activities are complete, ask the user to rate the overall experience using the NASA-TLX ratings and scales one last time.

This step results in another number that gauges and the overall workload and demand the user feels while using the app.

(Note that prior exposure or experience with an app can create familiarity and comfort when using it. This process works best if the user has no prior experience with the app OR by evaluating with multiple users with the same level of experience.)

Here are some results. I'm displaying the workload scores for both the desktop and mobile versions of Asana and Trello (higher numbers indicate a higher weighted workload rating or ‘heavier’ user experience, and lower scores indicate a lower weighted workload rating or ‘lighter’ user experience):

As you can see in the chart, this user found the Trello mobile app to have the highest overall load with a highest overall ‘TLX’ score of 47, with the Asana mobile app close behind at 44 overall.

Based on his scores, this user appears to find it more to demanding overall to use the mobile version of both applications, particularly when it comes to the ‘share and collaborate’ activity (high scores of 80 and 82, yikes!). So, now that we’ve got the numbers we can ask Why is the mobile ux so heavy? and What can be done about it?

As is good practice in ux research, I observed the user closely while he was doing these activities. During the share and collaborate activity for both mobile apps the user was forced to switch back his desktop in order add a contact so that he could share a task with them using his iPhone. As demonstrated by his ratings, having to use multiple devices created an equally ‘heavy’, or cumbersome experience for both the mobile apps. If the designers and developers can solve this issue, they you can raise the overall lightness of the mobile app experience.

NASA-TLX scales also provide the opportunity to dig a little deeper into exactly which source of demand is most impacting the user. Here we’ll look a little deeper into this user's overall ratings for both Asana mobile and Trello mobile:

These data represent two sets of numbers: the rating that the user gave a particular source of demand when using the mobile app, and also how impactful he felt that particular source was on the experience (noted here as weight). We see that the user rated mental demand, physical demand, effort, and frustration high when using the Trello mobile app, and mental demand and frustration particularly high when using the Asana mobile app. This user also weighted the physical demand and effort sources of workload as more impactful in the Trello in the experience overall, contributing to its slightly larger overall score workload score of 47.

So what could the Asana and Trello app designers and developers take away from this particular example? That making users have to switch back to their desktop in order to complete activities on their mobile (for example) can create physical demand, higher effort, and even frustration for users, leading to an overall 'heavier' perceived experience.

I've shown here that it is possible to measure and understand the weight of a user experience, as well as pinpoint why through observation. So product teams can (and should) feel empowered to ‘lighten up’ their experience for their users, creating better tools and enabling users to get back to focusing on what they care about.