UX Deep Dive Mini-Series: Part 2 - Task Success Rate
Quantifying Design: Key Data for Evaluating Your Work
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UX Deep Dive Mini-Series: Part 2 - Task Success Rate
Our business partners are obsessed with conversion rates. After all, whether a user takes action or completes a transaction is one of the easiest ways to measure success. However, for designers, success goes beyond conversion rates. We care about how easily and confidently our users complete their tasks. If users stumble, get stuck, or abandon tasks midway, conversion rates will inevitably suffer. But how can we communicate the impact of usability on overall business objectives?
That’s where Task Success Rate (TSR) comes in. But how do we measure it? How do we use it to diagnose issues and improve our designs?
What is Task Success Rate?
Definition: Task Success Rate or Task Completion Rate is a metric that measures the percentage of users who successfully complete a specific task or set of tasks on a website or application. (Source: Okrify)
How is it calculated?
Example:
If 100 users attempt to book a flight and 85 succeed, the Task Success Rate is 85%.
How is Task Success Rate Different from Conversion Rate?
Note: In the first newsletter of the Mini Deep Dive series, we covered Conversion Rates. We will be referring to use case later in this article. Reading the first newsletter will provide context but isn’t mandatory.
Task Success Rate focuses on usability and user experience, while conversion rates align with business objectives. TSR highlights user pain points, such as confusing workflows or unnecessary steps, even when those aren’t directly tied to business outcomes.
Scenario 1: Redesigning an E-commerce Checkout Flow
TSR: Evaluate steps like filling out shipping information or selecting a payment method.
Conversion Rate: Measure the percentage of users who complete the checkout process.
Scenario 2: Launching a New Feature
TSR: Ensure users can find and use the feature effectively.
Conversion Rate: Track if the feature increases subscriptions or upsells.
Why do we use Task Success Rate in UX?
Focuses on the User Journey: TSR evaluates the effectiveness of individual touchpoints.
Uncovers Pain Points: Identifies specific steps where users struggle, enabling targeted improvements.
Prioritizes Usability: A high TSR indicates designs that help users achieve their goals effortlessly.
Did You Know? Studies show that improving usability can increase task success rates by up to 50%, boosting both satisfaction and retention.
Common Problems That Affect Task Success Rate
A high TSR is about more than sleek design—it’s about removing friction. Common barriers include:
Unclear Navigation: Users cannot find where to start or what to do next.
Example: Missing or poorly labeled buttons can leave users confused.
Overly Complex Workflows: Tasks require unnecessary steps or inputs.
Example: Requiring a billing address for a free download.
Confusing Error Messages: Poor error handling makes recovery difficult.
Example: “An error occurred” without further guidance.
Lack of Guidance: No tooltips, hints, or progress indicators to assist users.
Example: A multi-step form without a progress bar.
Conversion case study:
Optimizing the flight booking checkout process
Problem:
Users on an online travel agency’s website seem to struggle with the critical steps in the flight booking process, leading to over 50% drop-offs on the checkout page. Despite investing time filling in detailed passenger info, many abandon the process halfway. Key pain points included:
Confusing workflows: Users were unsure about the next steps in the process. They also get distracted by the large amount of information presented to them.
Unclear fee breakdowns: A lack of transparency around charges and policies created hesitation and frustration.
Poor error handling: When mistakes occur during the checkout process, the users were often confused and frustrated as they didn’t know what caused the issue and how they can fix it.
Solution:
The team focused on improving Task Success Rate (TSR) by streamlining the checkout flow and addressing usability barriers:
1️⃣ Streamlined Workflows and Guidance
Simplified steps with a focus on progressive disclosure, allowing users to tackle one task at a time (e.g., Users must complete the passenger information section before moving on to seat selection.)
Added a progress indicator to help users understand their position in the process and what’s next.
2️⃣ Transparency in Charges and Data Collection
Displayed a clear, itemized breakdown of charges (ticket price, taxes, fees) with concise explanations.
Explained why personal data was required, ensuring compliance and building trust. (e.g., Provided reassurance that the data collected as part of the Airline booking requirements and how they will be used)
3️⃣ Improved Error Handling and Recovery Options
Enhanced error messages to be actionable (e.g., “Please re-enter your credit card details”).
Provided users with easy ways to recover from mistakes without starting over with inline error validation.
Error validation for each section of the checkout flow as opposed to validating after the long form is submitted.
Result:
The improved checkout flow dramatically boosted the Task Success Rate:
Task Success Rate increased from 70% to 95%, reducing user frustrations and bottlenecks specifically around completion of traveller’s information (per various airlines’ requirements) and ticket inclusions.
Completion time for booking tasks decreased by 30%, creating a smoother and more efficient experience.
User satisfaction scores improved, with fewer support tickets and complaints about the checkout process.
How to Measure Task Success Rate
Define Key Tasks: Identify critical actions, like completing onboarding or checkout.
What are the critical actions of the onboarding flow?
What steps must the user take to complete the checkout successfully?
Conduct Usability Testing: Observe users, noting successes, failures, and confusion.
Are they confident with their decisions? Are they confused?
Use Analytics Tools: Track task completions with tools like Google Analytics or Mixpanel.
Do you need to add event tracking on the key tasks? What events should do we need to track?
Combine Data: Analyze metrics alongside user feedback to identify underlying issues.
What can we do to fix the issue? Are there opportunities for us to move the needle in other areas too?
Boosting Task Success Rate
Simplify Processes: Reduce unnecessary steps.
Example: Combine shipping and billing address fields when they are the same.
Provide Feedback: Use clear confirmation messages.
Example: “Your booking is confirmed!”
Improve Error Handling: Ensure messages are actionable.
Example: “Please enter a valid email address.”
Offer Guidance: Add tooltips or progress indicators.
Test Early and Often: Conduct usability tests during design iterations.
Task Success Rate is more than a metric—it’s a reflection of how well your designs serve real people. By tracking and optimizing TSR, you can create intuitive, effective user experiences that not only achieve business goals but also delight users.
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