How User Experience Principles Can Impact Online Conversion Rates

One of the greatest advantages of the Internet is its convenience. With just a few clicks (or taps), people can complete tasks that would previously require a whole afternoon.

The number of website users who complete a given task, such as completing a purchase or creating an account, out of the total number of visitors is known as a conversion rate. While conversion rates are most often associated with sales, they can also reflect the convenience of a site in the sense that a high conversion rate means that users are able to successfully complete non-sales-related tasks. 

In this article, we explore how two UX principles, Parkinson’s Law and the Goal-Gradient Effect, can guide users through a thoughtfully designed conversion flow which encourages task completion and results in higher conversion rates on digital platforms.

The Principles

Parkinson’s Law

Parkinson’s Law was originally published by Cyril Nothcote Parkinson in The Economist in 1955. It states that “Any task is prolonged until the time available for doing it is completely exhausted”. For example, when a person is given a week to complete a task that should only take a day, more often than not, the task will be prolonged to span the entire week. In digital terms, consider a user making an online purchase – a process which collects only the most essential information will ensure user focus. Time-to-completion should not be prolonged by non-essential steps or decision points that could delay the user from completing the transaction. 

The Goal-Gradient Effect

A common counterpart to Parkinson’s Law when dealing with conversion flows is the Goal-Gradient Effect. The Goal-Gradient Effect states that “The tendency to approach a goal increases with proximity to the goal.” Consider a 1,200 piece jigsaw puzzle Each time you complete a “puzzle milestone”, such as a corner or edge of the puzzle, you’re motivated to finish the other three edges — and, eventually, the rest of the puzzle. Now consider if you didn’t actually know how many edges the puzzle had, or what the final picture even was? With no end in sight, what should be a rewarding past-time becomes an endless sea of uncertainty. 

A conversion flow is no different than a jigsaw puzzle in the sense that each experience includes a goal and milestones (except digital-conversion flows should be easier and faster). Along this flow, a user should only spend necessary time on each step (Parkinson’s Law) and should be able to see what they’ve done so far and how much left they have to do (Goal-Gradient Effect).

Application to Conversion Flow Theory

To ensure a user is given the correct amount of time per step during conversion flows, we first need to understand how people perceive time in the digital space. User experience researcher Jakob Nielson describes time perception via  two factors – responsiveness and the number of decision points between point A and point B.

Website Response Times

In his book Usability Engineering Nielsen describes website response time as the time a user waits between performing an action and experiencing feedback. Users are people, and as people we expect responses to the things we do. We ask a friend a question face-to-face, at the very least we expect acknowledgement that we’ve been heard. We order lunch at the restaurant, before receiving the food, we expect confirmation that our order has been received.

People expect similar feedback in the digital space. After filling out some credit card information to make an online purchase, a behind-the-scenes process which verifies the information entered. In a second article, Nielsen  describes how, after submitting a form, if a user is not instantly taken to the next step, it takes between just 0.1 and 1 second for them to feel as though they are waiting. It is important to at least acknowledge that a button has been clicked and something is in fact happening. Designers must craft their experiences so that all actions provide feedback to reduce the amount of user uncertainty. Acknowledgement of their actions and being aware of when they can move forward allows users to feel in-control of their experience.

Amount of Decision Making

A second factor of the perception of time it takes to complete a task is the amount of decisions a user must make before reaching their goal. Neilson’s argues that basic tasks should be completed as quickly as possible and take no longer than 1 minute. Inflating a basic task with optional steps and requiring a user to make micro decisions unrelated to their goal puts the user at risk to lose focus, become irritated, or worst of all change their mind about the end goal altogether.

According to Parkinson’s Law 1) If a system is not responsive a user may think they have time to do something in between actions if the first action appears to have not been received or has no ET and 2) If a path contains many sub paths, it is likely that a user will explore all of these paths and possibly get lost, never making it to their destination. 

Utilizing Goal-Driven Behavior

With the perception of time in mind, the Goal-Gradient Effect can increase conversion by providing a map of a journey with a reward. This guide improves usability of the flow and ensures them that reaching the end is feasible and fulfilling.

An interface featuring a visual representation of steps completed and steps remaining allows a user to easily perceive the amount of time till their goal is reached. American Behaviouralist, Clark Leonard Hull, performed a study to test the Goal-Gradient theory by recording the behavior of rats who ran towards rewards at the end of mazes vs. rats who were given rewards at the beginning of a maze. He was able to conclude that a rat’s performance increased as they approached rewards at the end of the maze. This theory was then applied to humans. Through various experiments, Hull was able to prove that people’s rate of progression towards the end of a path increased as they approached a reward if the reward was perceived as feasible in the first place. 

Conversion flows are goal-oriented in the sense that the user’s goal is to complete a purchase for something they wish to buy. With a reward in sight and a clear path right to it, users are much more likely to convert. 

Application to the Design of Conversion Flow 

Conversion flows are nothing new to the online experience. Over time, based on on-going user research and feedback, numerous patterns support a balance between Parkinson’s Law and the Goal-Gradient Effect, including limited checkout steps, microinteractions, and progress bars.

Limiting Checkout flow to Checkout Steps

Users should already know exactly what they are buying by the time they reach the checkout step. Their singular goal is to pay for their items and ensure that they will get delivered to the correct place. Unlike a real life line at the register the online checkout process does not have the luxury of a physical line which the customer must remain in in order to reach their goal. Online, if at any moment, the user is required to make other decisions, they are at risk to abandon their path to checkout.

The checkout flow should be designed to take the least amount of time possible. This means including smart defaults or saved preferences for fields such as shipping or billing addresses, credit card numbers, etc (with security compliance in mind of course).This allows a user to have to do less manual work and will get them to the end goal even faster. 

For example, consider the Amazon checkout process pictured above. On this screen there are no distractions – all the options to buy similar products or “likely bought together” products, choose between vendors, set quantity or colors, indicating whether it is a gift, etc. is done before the user gets to this flow. Because the user is also already signed in, there is a default set for all required values and all the user has to do is confirm them (or change only if necessary). One of Amazon’s prime user types, repeat customers, can checkout in just three clicks (quite scary actually). 

Including Micro-Interactions 

A checkout flow should be responsive to ensure users that they are always moving towards their goal. Micro-Interactions, small visual cues triggered by actions within a larger process, can be used to provide feedback that a behind the scenes process is happening. Mini processes during this stage should never take more than a few seconds (in order to keep the task within the 1 minute task attention span) and when they do, a visual indicator will ensure that the user waits and remains in the checkout flow rather than wonder if the system froze, leave the system or feel like they have to hit the refresh button and start over. 

Micro-Interactions can also assist the user in filling out fields in order to speed up the task. For example, allowing auto-complete on shipping addresses and/or including a “Same as shipping” option for billing address could save your user from having to enter repeat information.

Displaying a Usable Progress Bar

Including a progress bar during a conversion flow is also key to a user’s success in completing their task. A progress bar is a visual aid which displays progress through a sequence by breaking it up into logical, numbered steps. A well designed progress bar allows a user to know what is happening now, what has just happened, and what will happen next. A clear and concise design plays a key part in assisting the user along their way. 

The foundation of a progress tracker starts with understanding the business needs and determining what is absolutely necessary for the user to do during this flow. Any actions deemed otherwise should not be inserted into the flow. Once the simplest, fastest path from point a to point b is formed, a progress tracker should inform the user exactly what those steps are and the visual design of the trackers to indicate that the user will be moving forward through them. 



Amazon (Amazon incorporates prior steps and inserts repeat users in the middle of the flow almost like an express lane)

Parkinson’s Law and the Goal-Gradient Effect have shaped the efficiency and convenience of conversion-based tasks. While users won’t come to your site or buy your products just to experience the easy checkout, a well designed conversion flow can increase the rate at which a user can commit to their decision and reach their goal.  


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