Continuous improvement is no longer a luxury—it’s a necessity. One of the most powerful tools in your optimization arsenal is A/B testing, a method that allows you to make informed decisions based on real user data. But how do you create a framework that consistently delivers results? This comprehensive guide will walk you through the process of building a robust A/B testing framework that drives continuous improvement and boosts your bottom line.
Understanding A/B Testing: The Foundation of Data-Driven Decision Making
A/B testing, also known as split testing, is a method of comparing two versions of a webpage or app against each other to determine which one performs better. It’s the cornerstone of data-driven decision making in digital marketing and product development.
What is A/B Testing?
At its core, A/B testing involves:
- Creating two versions of a page or feature (Version A and Version B)
- Randomly showing these versions to different segments of visitors
- Collecting data on how each version performs
- Analyzing the results to determine which version is more effective
This simple yet powerful approach allows businesses to make informed decisions based on actual user behavior rather than gut feelings or assumptions.
The Scientific Method in Action
A/B testing is essentially the scientific method applied to digital optimization. It follows a similar process:
- Observation: Identify areas for improvement
- Hypothesis: Propose a change that might lead to better results
- Experiment: Implement the change for a subset of users
- Analysis: Measure the results and draw conclusions
- Implementation: Roll out successful changes and iterate on failures
By following this systematic approach, businesses can continuously refine their digital presence and improve user experience.
The Business Case for A/B Testing: Why It Matters
In an increasingly competitive digital landscape, A/B testing isn’t just nice to have—it’s essential for staying ahead. Here’s why:
1. Improved ROI on Marketing Spend
By systematically testing different elements of your marketing campaigns, you can optimize for the highest return on investment (ROI). This means more bang for your marketing buck.
2. Enhanced User Experience
A/B testing allows you to understand what resonates with your audience, leading to a better user experience. This, in turn, can lead to higher engagement, loyalty, and conversions.
3. Data-Driven Decision Making
Instead of relying on intuition or HiPPO (Highest Paid Person’s Opinion), A/B testing provides concrete data to inform decisions. This reduces risk and increases the likelihood of success.
4. Continuous Improvement
A robust A/B testing framework creates a culture of continuous improvement. Small, incremental gains can compound over time, leading to significant long-term growth.
5. Competitive Advantage
Companies that effectively leverage A/B testing can outpace competitors by rapidly iterating and improving their digital offerings.
Key Components of a Robust A/B Testing Framework
A successful A/B testing framework consists of several critical components:
- Clear Objectives: Define what you want to achieve with your testing program.
- Hypothesis-Driven Approach: Base your tests on well-formed hypotheses.
- Rigorous Methodology: Ensure your tests are statistically valid and free from bias.
- Appropriate Tools: Use reliable A/B testing software and analytics platforms.
- Cross-Functional Collaboration: Involve stakeholders from various departments.
- Documentation and Knowledge Sharing: Keep detailed records of tests and share learnings.
- Iterative Process: Use insights from each test to inform future experiments.
Let’s dive deeper into each of these components in the following sections.
Setting Up Your A/B Testing Infrastructure
Before you can start running effective A/B tests, you need to have the right infrastructure in place. Here’s how to set up a solid foundation:
1. Choose the Right A/B Testing Tool
There are numerous A/B testing tools available, each with its own strengths. Some popular options include:
- Optimizely (enterprise-level features)
- VWO (Visual Website Optimizer, user-friendly interface)
- AB Tasty (AI-powered testing and personalization)
When selecting a tool, consider factors such as:
- Ease of use
- Integration with your existing tech stack
- Advanced features like multivariate testing
- Pricing and scalability
2. Set Up Proper Tracking
Ensure you have robust analytics in place. This typically involves:
- Implementing Google Analytics or a similar web analytics tool
- Setting up conversion tracking
- Defining key performance indicators (KPIs)
- Creating custom events and goals
3. Establish a Testing Process
Develop a standardized process for proposing, prioritizing, and executing tests. This should include:
- A test request form
- A prioritization framework (e.g., ICE – Impact, Confidence, Ease)
- A testing calendar
- Roles and responsibilities for team members
4. Create a System for Documentation
Implement a system for documenting test hypotheses, results, and learnings. This could be:
- A dedicated testing log in a spreadsheet
- A project management tool like Trello or Asana
- A wiki or internal knowledge base
5. Ensure Technical Readiness
Make sure your website or app is technically prepared for A/B testing:
- Implement a tag management system for easy deployment of testing scripts
- Ensure your site loads quickly to avoid impacting user experience during tests
- Set up a staging environment for testing implementations before going live
By establishing this infrastructure, you’ll be well-positioned to run effective, insightful A/B tests that drive continuous improvement.
Developing a Hypothesis-Driven Testing Strategy
A robust A/B testing framework is built on a foundation of strong hypotheses. Here’s how to develop a hypothesis-driven testing strategy:
1. Understand the Anatomy of a Good Hypothesis
A well-formed hypothesis should include:
- The change you want to make
- The expected outcome
- The reasoning behind your expectation
For example: “By changing the CTA button color from green to red, we expect to see a 10% increase in click-through rate because red creates a sense of urgency.”
2. Use Data to Inform Your Hypotheses
Don’t test blindly. Use existing data to guide your hypotheses:
- Analyze user behavior data from tools like Google Analytics
- Review heatmaps and session recordings
- Conduct user surveys and interviews
- Examine customer support inquiries
3. Prioritize Your Hypotheses
Not all hypotheses are created equal. Prioritize based on:
- Potential impact on key metrics
- Ease of implementation
- Confidence in the hypothesis (based on data and research)
Tools like the PIE framework (Potential, Importance, Ease) can help with prioritization.
4. Create a Hypothesis Backlog
Maintain a list of potential hypotheses to test. This ensures you always have ideas ready when resources become available.
5. Refine Hypotheses Based on Past Tests
Use insights from previous tests to inform future hypotheses. This creates a cycle of continuous learning and improvement.
By following these steps, you’ll create a testing strategy that is focused, data-driven, and primed for success.
Choosing the Right Metrics: Beyond Conversion Rates
While conversion rate is often the north star metric for A/B testing, it’s crucial to look beyond this single data point. Here’s how to choose the right metrics for your tests:
1. Understand Different Types of Metrics
- Primary Metrics: The main goal of your test (e.g., conversion rate)
- Secondary Metrics: Supporting metrics that provide context (e.g., engagement rate)
- Guardrail Metrics: Metrics that ensure you’re not improving one area at the expense of another (e.g., average order value)
2. Align Metrics with Business Goals
Ensure your chosen metrics tie directly to your overall business objectives. For example:
- If your goal is to increase customer lifetime value, look at metrics like repeat purchase rate or average order frequency
- If you’re focused on user engagement, consider time on site, pages per session, or return visitor rate
3. Consider Both Macro and Micro Conversions
- Macro Conversions: The primary goals (e.g., purchases, sign-ups)
- Micro Conversions: Smaller actions that lead to macro conversions (e.g., adding items to cart, viewing product pages)
4. Look at Short-Term and Long-Term Impacts
Some changes might show immediate results, while others may take time to reveal their full impact. Consider metrics that capture both:
- Short-term: Click-through rate, bounce rate
- Long-term: Customer lifetime value, retention rate
5. Use Segmentation
Different user segments may respond differently to your tests. Break down your metrics by:
- New vs. returning visitors
- Traffic source
- Device type
- Geographic location
6. Don’t Forget Qualitative Metrics
While quantitative data is crucial, qualitative insights can provide valuable context. Consider:
- User feedback
- Customer support inquiries
- Social media sentiment
By choosing a comprehensive set of metrics, you’ll gain a more holistic view of your test results and make more informed decisions.
Sample Size and Statistical Significance: Ensuring Reliable Results
One of the most critical aspects of A/B testing is ensuring that your results are statistically significant. This means that the differences you observe between variants are likely due to the changes you made, rather than random chance. Here’s how to approach this:
1. Understand Statistical Significance
Statistical significance is typically expressed as a p-value, which represents the probability that the observed results occurred by chance. In A/B testing, a p-value of 0.05 or less (95% confidence) is often considered statistically significant.
2. Calculate Required Sample Size
To determine the sample size needed for a statistically significant result, consider:
- Baseline conversion rate
- Minimum detectable effect (the smallest improvement you care about)
- Desired statistical power (typically 80%)
- Significance level (typically 95%)
Use an A/B test sample size calculator to determine the required number of visitors for each variant.
3. Avoid Stopping Tests Too Early
It’s tempting to end a test as soon as you see a winner, but this can lead to false positives. Always wait until you’ve reached your predetermined sample size.
4. Be Aware of External Factors
Seasonal changes, marketing campaigns, or other external events can impact your results. Consider running your tests for full weeks to account for day-of-week variations.
5. Use Segmentation Carefully
While segmentation can provide valuable insights, it also reduces your sample size for each segment. Ensure you have enough traffic to support segmented analysis.
6. Consider Bayesian vs. Frequentist Approaches
Traditional A/B testing uses a frequentist approach, but Bayesian methods are gaining popularity. Bayesian statistics can provide more intuitive results and allow for more flexible stopping rules.
By paying close attention to sample size and statistical significance, you’ll ensure that your A/B testing results are reliable and actionable.
Test Duration: Finding the Sweet Spot
Determining the right duration for your A/B tests is crucial. Run them too short, and you risk making decisions based on incomplete data. Run them too long, and you delay potential improvements. Here’s how to find the right balance:
1. Consider Your Traffic Volume
High-traffic sites can reach statistical significance faster than low-traffic ones. Use your sample size calculations to estimate how long it will take to reach the required number of visitors.
2. Account for Conversion Cycle
If your conversion process typically takes several days (e.g., in B2B sales), ensure your test runs long enough to capture the full cycle.
3. Run Tests for Full Week Increments
To account for day-of-week variations, always run tests for complete weeks. This is especially important for businesses with weekly patterns.
4. Be Mindful of Seasonal Effects
If your business experiences seasonal fluctuations, ensure your test duration doesn’t span across different seasons unless that’s specifically what you’re testing for.
5. Use Time-Based Cohorts
For tests that might have long-term effects (e.g., onboarding changes), consider using time-based cohorts to track users over an extended period.
6. Avoid Peeking
Resist the urge to continually check results before reaching your predetermined sample size. This can lead to false positives and incorrect conclusions.
7. Set a Maximum Duration
Even if you haven’t reached statistical significance, set a maximum duration for your tests (e.g., 4-8 weeks). If you haven’t seen significant results by then, it might be time to move on to a new hypothesis.
By carefully considering these factors, you can determine an appropriate test duration that balances speed with reliability.
Analyzing and Interpreting Test Results
Once your A/B test has run its course, it’s time to analyze and interpret the results. This crucial step will inform your decision-making and guide future optimizations. Here’s how to approach it:
1. Look Beyond Just Winners and Losers
While it’s important to identify which variant performed better, don’t stop there. Dig deeper to understand why certain changes led to the observed results.
2. Segment Your Results
Break down your results by different user segments:
- New vs. returning visitors
- Traffic sources
- Device types
- Geographic locations
This can reveal insights that might be hidden in the overall results.
3. Consider All Metrics
Don’t focus solely on your primary metric. Look at how the test affected your secondary and guardrail metrics as well. A positive change in one area might have unintended consequences in another.
4. Analyze Statistical Significance
Ensure your results are statistically significant before drawing conclusions. Be wary of declaring a winner too soon, especially if the difference is small.
5. Look for Trends Over Time
Examine how the results evolved over the course of the test. Were there any sudden changes or gradual shifts?
6. Consider External Factors
Think about any external events or changes that might have influenced your results, such as marketing campaigns, competitor actions, or seasonal effects.
7. Qualitative Analysis
Don’t neglect qualitative data. User feedback, support tickets, and other qualitative insights can provide context for your quantitative results.
8. Document Your Findings
Create a detailed report of your test results, including:
- Test hypothesis
- Variants tested
- Key metrics and results
- Segmented data
- Insights and learnings
- Recommendations for next steps
9. Share Results Widely
Communicate your findings to stakeholders across the organization. This promotes a culture of data-driven decision-making and can inspire ideas for future tests.
10. Plan Your Next Steps
Based on your analysis, decide on your next course of action:
- Implement the winning variant
- Run a follow-up test to validate or expand on the results
- Use the insights to inform new hypotheses
By thoroughly analyzing and interpreting your test results, you’ll extract maximum value from your A/B testing efforts and drive continuous improvement.
Implementing Winners and Iterating on Losers
The true value of A/B testing lies not just in running tests, but in effectively implementing the winners and learning from the losers. Here’s how to make the most of your test results:
Implementing Winning Variants
- Validate the Results: Before full implementation, consider running a follow-up test to confirm the results, especially for high-impact changes.
- Plan the Rollout: Develop a clear plan for implementing the winning variant, including timelines and responsible team members.
- Monitor Post-Implementation: Keep a close eye on your metrics after implementing the change to ensure it performs as expected in the wild.
- Document the Process: Record the entire testing and implementation process for future reference and to build your testing knowledge base.
Learning from and Iterating on Losing Variants
- Analyze Thoroughly: Dig deep into why a variant didn’t perform as expected. There’s often as much to learn from failures as from successes.
- Generate New Hypotheses: Use insights from the losing variant to inform new test ideas. Perhaps a different approach to solving the same problem could yield better results.
- Consider Segmentation: A losing variant overall might have performed well for certain user segments. Consider if there’s value in a segmented implementation.
- Iterate and Retest: Don’t be afraid to refine and retest ideas. Sometimes small tweaks can turn a loser into a winner.
Continuous Improvement Cycle
Implement a cycle of continuous improvement:
- Implement winners
- Learn from losers
- Generate new hypotheses
- Prioritize and test
- Analyze results
- Repeat
This iterative process is the key to long-term success in A/B testing and conversion rate optimization.
Building a Culture of Experimentation
Creating a robust A/B testing framework isn’t just about tools and processes—it’s about fostering a culture of experimentation throughout your organization. Here’s how to build and nurture this culture:
1. Lead by Example
Leadership should champion the importance of data-driven decision making and experimentation. When leaders ask for data to support decisions, it sets the tone for the entire organization.
2. Encourage Hypothesis Generation
Create channels for all team members to submit test ideas. This could be through regular brainstorming sessions or a dedicated ideas board.
3. Celebrate Learning, Not Just Wins
Emphasize that the goal of testing is to learn, not just to find winners. Celebrate tests that provide valuable insights, even if they don’t result in immediate gains.
4. Share Results Widely
Make test results accessible to everyone in the organization. Regular newsletters or dashboards can keep everyone informed and engaged in the testing process.
5. Provide Training and Resources
Invest in training for your team on A/B testing principles, statistical analysis, and your chosen testing tools. The more people understand the process, the more they’ll engage with it.
6. Integrate Testing into Product Development
Make A/B testing a standard part of your product development process. New features should be tested before full rollout whenever possible.
7. Foster Cross-Functional Collaboration
Encourage collaboration between different departments (e.g., marketing, product, engineering) in the testing process. Different perspectives can lead to more innovative test ideas.
8. Set Experimentation KPIs
Include experimentation-related KPIs in your business metrics. This could include the number of tests run, insights generated, or improvements implemented.
9. Allow for Failure
Create a safe environment where failed tests are seen as valuable learning opportunities rather than mistakes.
10. Continuously Refine Your Process
Regularly review and optimize your testing process itself. Apply the principles of continuous improvement to your experimentation framework.
By fostering a culture of experimentation, you’ll not only improve your A/B testing outcomes but also drive innovation and growth throughout your organization.
Advanced A/B Testing Techniques
As you become more proficient with A/B testing, you can explore more advanced techniques to gain deeper insights and drive greater improvements. Here are some advanced A/B testing methods to consider:
1. Multivariate Testing
While A/B testing compares two versions of a page, multivariate testing allows you to test multiple variables simultaneously. This can help you understand how different elements interact with each other.
2. Sequential Testing
Instead of waiting for a fixed sample size, sequential testing allows you to continuously monitor results and stop tests as soon as statistical significance is reached.
3. Multi-Armed Bandit Testing
This approach dynamically allocates more traffic to better-performing variants during the test, allowing you to capitalize on winners more quickly.
4. Personalization Testing
Test different experiences for different user segments to optimize the experience for each group.
5. Machine Learning-Driven Testing
Leverage machine learning algorithms to dynamically optimize experiences based on user behavior and characteristics.
6. Cross-Browser and Cross-Device Testing
Ensure your tests account for different browsers and devices to provide a consistent experience across platforms.
7. Server-Side Testing
Move beyond client-side testing to perform more robust, scalable tests at the server level.
8. Fake Door Testing
Test user interest in new features or products before actually building them by creating a fake entry point and measuring engagement.
9. Holdout Groups
Maintain a group of users who don’t see any changes to measure the long-term impact of your optimizations.
10. Longitudinal Studies
Track cohorts of users over time to understand the long-term effects of changes on user behavior and lifetime value.
By incorporating these advanced techniques into your A/B testing framework, you can uncover deeper insights and drive more significant improvements in your digital experiences.
Common Pitfalls and How to Avoid Them
Even with a robust framework in place, there are several common pitfalls that can undermine your A/B testing efforts. Here’s how to identify and avoid them:
1. Running Tests Without a Clear Hypothesis
Pitfall: Testing randomly without a clear rationale.
Solution: Always start with a well-defined hypothesis based on data and user insights.
2. Stopping Tests Too Early
Pitfall: Ending tests as soon as you see a winner, leading to false positives.
Solution: Determine your sample size in advance and stick to it, regardless of early results.
3. Ignoring Statistical Significance
Pitfall: Making decisions based on results that aren’t statistically significant.
Solution: Ensure you understand and apply the principles of statistical significance in your analysis.
4. Neglecting Site Speed
Pitfall: Implementing tests that significantly slow down your site.
Solution: Monitor site speed as a key metric in your tests and optimize your testing setup for performance.
5. Testing Too Many Elements at Once
Pitfall: Creating overly complex tests that make it difficult to isolate the impact of individual changes.
Solution: Start with simpler A/B tests before moving to more complex multivariate tests.
6. Failing to Consider External Factors
Pitfall: Attributing all observed changes to your test without considering external influences.
Solution: Be aware of other factors (like seasonality or marketing campaigns) that might impact your results.
7. Not Learning from “Losing” Tests
Pitfall: Discarding tests that don’t produce a winner without analyzing why.
Solution: Treat every test as a learning opportunity, regardless of the outcome.
8. Overgeneralizing Results
Pitfall: Assuming that what works for one page or segment will work for all.
Solution: Be cautious about applying insights too broadly and always test before widespread implementation.
9. Neglecting Mobile Users
Pitfall: Focusing solely on desktop experiences in your tests.
Solution: Ensure your testing strategy includes mobile experiences, and segment results by device type.
10. Not Considering Long-Term Effects
Pitfall: Making decisions based solely on short-term metrics without considering long-term impact.
Solution: Include long-term metrics in your analysis and consider running extended tests for major changes.
By being aware of these common pitfalls and taking steps to avoid them, you can ensure that your A/B testing efforts yield reliable, actionable insights that drive real improvement.
Case Studies: Real-World A/B Testing Successes
To illustrate the power of a robust A/B testing framework, let’s look at some real-world examples of successful tests that drove significant improvements:
Case Study 1: Booking.com’s Continuous Experimentation
Challenge: Optimize the user experience to increase bookings.
Approach: Booking.com runs thousands of concurrent tests, from minor UI tweaks to major feature changes.
Result: This culture of continuous experimentation has helped Booking.com become a leader in the online travel industry, with improvements in conversion rates, user engagement, and customer satisfaction.
Key Takeaway: Embracing a culture of experimentation can drive continuous improvement and maintain a competitive edge.
Case Study 2: Amazon’s Add to Cart Button
Challenge: Increase the number of items added to carts.
Approach: Amazon tested changing their “Add to Cart” button to “Add to Basket” for UK users.
Result: The “Add to Basket” variant increased sales by 49%.
Key Takeaway: Even small changes in wording can have a significant impact on user behavior.
Case Study 3: Electronic Arts (EA) Registration Flow
Challenge: Simplify the game registration process to increase completions.
Approach: EA tested a single-page registration form against their original multi-page process.
Result: The single-page form increased registration completion by 40%.
Key Takeaway: Reducing friction in critical user journeys can lead to substantial improvements in conversion rates.
Case Study 4: Humana’s Homepage Redesign
Challenge: Improve engagement and lead generation on the homepage.
Approach: Humana tested a complete redesign of their homepage, focusing on simplifying navigation and highlighting key services.
Result: The new design led to a 433% increase in click-throughs to key insurance products.
Key Takeaway: Sometimes bold, comprehensive changes can yield dramatic improvements.
Case Study 5: The Guardian’s Membership Drive
Challenge: Increase digital subscriptions.
Approach: The Guardian tested different messaging and layouts for their membership appeal.
Result: One variant increased click-through rates to the membership page by 12%, leading to significant growth in digital subscriptions.
Key Takeaway: Testing different value propositions and messaging can help identify what resonates most with your audience.
These case studies demonstrate the wide-ranging impact that A/B testing can have across industries and types of digital experiences. By applying similar principles and maintaining a rigorous testing framework, you too can uncover insights that drive substantial improvements in your key metrics.
Tools and Resources for Effective A/B Testing
To implement a robust A/B testing framework, you’ll need the right tools and resources. Here’s a curated list to get you started:
A/B Testing Platforms
- Optimizely: Enterprise-level platform with advanced features and machine learning capabilities.
- VWO (Visual Website Optimizer): User-friendly platform with a visual editor and advanced targeting options.
- AB Tasty: AI-powered testing and personalization platform.
- Convert: Privacy-focused A/B testing tool with GDPR compliance features.
Analytics Tools
- Google Analytics: Essential for understanding user behavior and segmenting test results.
- Mixpanel: Event-based analytics tool for tracking user interactions.
- Amplitude: Product analytics platform for deeper insights into user behavior.
Heat Mapping and User Behavior Tools
- Hotjar: Provides heatmaps, session recordings, and user feedback tools.
- Crazy Egg: Offers heatmaps, scrollmaps, and user recordings.
- FullStory: Digital experience analytics platform with session replay and funnel analysis.
Statistical Significance Calculators
- Optimizely’s Sample Size Calculator: Helps determine required sample size for tests.
- AB Testguide’s Calculator: Calculates statistical significance of test results.
- VWO’s A/B Test Significance Calculator: Another tool for checking the validity of your results.
Learning Resources
- Conversion XL Blog: Offers in-depth articles on CRO and A/B testing.
- Optimizely’s Knowledge Base: Comprehensive resource for learning about A/B testing.
- Nielsen Norman Group: Provides research-based articles on UX and A/B testing.
- “A/B Testing: The Most Powerful Way to Turn Clicks Into Customers” by Dan Siroker and Pete Koomen: Comprehensive book on A/B testing strategies.
Communities and Forums
- GrowthHackers: Community of growth-focused marketers sharing insights and strategies.
- ConversionXL Community: Forum for conversion optimization professionals.
- Reddit’s r/ABTesting: Subreddit dedicated to A/B testing discussions.
API and Developer Tools
- Optimizely’s Full Stack: For server-side and application testing.
- Split.io: Feature flagging and experimentation platform for developers.
- LaunchDarkly: Feature management platform with A/B testing capabilities.
By leveraging these tools and resources, you’ll be well-equipped to implement and maintain a robust A/B testing framework that drives continuous improvement in your digital experiences.
Conclusion: Embracing Continuous Improvement Through A/B Testing
In today’s fast-paced digital landscape, the ability to continuously improve and optimize your online presence is not just an advantage—it’s a necessity. A robust A/B testing framework provides the foundation for this ongoing evolution, allowing you to make data-driven decisions that enhance user experience, drive conversions, and ultimately, grow your business.
Throughout this guide, we’ve explored the key components of an effective A/B testing framework:
- Understanding the fundamentals of A/B testing and its business impact
- Setting up the right infrastructure and choosing appropriate tools
- Developing a hypothesis-driven testing strategy
- Selecting meaningful metrics and ensuring statistical validity
- Analyzing results and implementing winners
- Building a culture of experimentation
- Exploring advanced techniques and avoiding common pitfalls
Remember, A/B testing is not a one-time effort, but an ongoing process of learning and refinement. Each test, whether it produces a clear winner or not, provides valuable insights into your users’ preferences and behaviors. By consistently applying these principles and iterating on your approach, you’ll be able to create digital experiences that truly resonate with your audience and drive business success.
As you embark on or continue your A/B testing journey, stay curious, remain data-driven, and never stop experimenting. The digital landscape is always evolving, and so should your approach to optimization. Embrace the power of A/B testing, and let it guide you towards continuous improvement and innovation.
Your path to digital optimization starts here. Are you ready to transform your approach to A/B testing and unlock new levels of performance? Start building your robust A/B testing framework today, and watch as data-driven insights propel your digital presence to new heights.
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