Introduction
Site speed matters for:
- Users
- SEO
- Conversions
- Brand reputation
- Inclusiveness
- Accessibility
- Costs
- Business
Web performance optimization is costly:
- Web Performance Consultant: $1500/day
- Costs can accumulate quickly ($1 every 30 seconds)
Challenges in Validating Optimization Efforts
- Lack of impact evidence
- Projects can go wrong (e.g., migrations increasing TTFB)
Main reasons for ineffective validation:
- Inadequate tools/data
- Inadequate metrics
- Unclear expectations
How to Validate Site Speed Efforts
1. Set a Baseline
- Set up the right tools
- Measure and know your current performance
- Get a performance history
2. Use Real User Monitoring (RUM)
- RUM provides real-time user data and interactions
- Benefits:
- Clear view of users' experience
- Ability to optimize and see the impact
3. Leverage RUM Data Effectively
Break down and segment the data:
- Device
- Connection type
- Location
- Navigation type
- CPU
- Device memory
- Page type
Analyze different segments for insights:
- Different locations may show varied performance
- Connection types can impact metrics like LCP
4. Use Appropriate Metrics
- Don't rely solely on averages
- Use percentiles (25th, 75th, 95th) for a more accurate representation
5. Focus on Atomic Optimizations
- Make optimizations small, isolated, and atomic
- Example: Adding "fetchpriority" high to hero image
- Specify metric, page type, device, and location
- Describe the optimization
- Plan how to measure the impact using RUM data
Key Takeaways
- Implement Real User Monitoring (RUM) and learn to use it effectively
- Use adequate metrics, focusing on percentiles rather than averages
- Perform atomic optimizations for easier validation
Action Points
- Set up RUM tools to collect real user data
- Create a baseline of your current site performance
- Segment your data based on various factors (device, location, connection type, etc.)
- Analyze performance across different segments
- Start using percentiles (25th, 75th, 95th) instead of averages for performance metrics
- Break down optimization efforts into small, atomic changes
- For each optimization:
- Clearly define the metric to improve
- Specify the segment (page type, device, location)
- Describe the optimization in detail
- Plan how to measure the impact using RUM data
- Regularly review and validate the impact of each optimization
- Continuously iterate and improve based on the data collected
By following these steps and focusing on data-driven, atomic optimizations, you can more effectively validate your site speed optimization efforts and ensure tangible improvements in user experience.