Assess, Diagnose, Fix: A Practical Approach to Technical SEO Issues

recently gave this talk at a Search Engine Strategies (SES) conference, where we explored a structured approach to identifying, diagnosing, and resolving technical SEO issues. Whether you were in the room or catching up here, this post will walk you through the key takeaways. I’ve also put together a Technical SEO Diagnostic Checklist you can download to apply these insights to your own site.

Why Technical SEO Matters

Technical SEO isn’t about keywords or content strategy—it’s about the mechanics of how search engines access, interpret, and rank your site. Without a healthy technical foundation, even the best content in the world won’t rank.

When something goes wrong, whether it’s a drop in rankings, an indexing issue, or a sudden traffic spike, you need a methodical approach to figure out:

• What’s happening? (Assessment)
• Why is it happening? (Diagnosis)
• How do we fix it? (Solution & Implementation)

Step 1: Assess the Situation

The symptoms never lie.

When diagnosing SEO issues, always start with a clear assessment. This means gathering data, looking for patterns, and identifying any red flags.

Key Checks for an SEO Assessment

• Traffic & Engagement Trends – Check Google Analytics/Search Console for unexplained spikes or drops.
• Site Search Check – Run site:yourdomain.com to see if expected pages appear and if any odd pages are indexed.
• Google Search Console Warnings – Look for indexation, mobile usability, or security issues.
• Page Speed & Core Web Vitals – Test with Lighthouse, PageSpeed Insights, or Web.dev.
• Crawl & Indexation Review – Use Screaming Frog, Sitebulb, or DeepCrawl to analyze how search engines access your site.
• Backlink Profile Audit – Check for lost, spammy, or suspicious links in Majestic or Ahrefs.

Red Flags to Watch For

• Sudden traffic loss without seasonality
• Unexpected deindexing of important pages
• Duplicate or thin content ranking instead of primary pages
• Site-wide ranking drops across multiple keywords
• An increase in 404 errors or broken links

If something looks off, it’s time to diagnose the problem.

Step 2: Diagnose the Root Cause

We know where the problem is. Now, what’s causing it?

At this stage, you’re shifting from data collection to analysis. The goal is to determine:

• What’s broken?
• Why is it broken?
• How do we fix it?

Common SEO Issues & How to Diagnose Them

• Traffic Drop? Check for algorithm updates, site changes, or manual penalties.
• Indexing Issues? Check robots.txt, noindex tags, and canonicalization conflicts.
• Slow Site Speed? Analyze server response time, image compression, and render-blocking scripts.
• Duplicate Content? Check canonical tags, hreflang conflicts, and pagination issues.
• Sudden Ranking Loss? Compare lost rankings in Search Console and cross-check backlinks.

If you can pinpoint what’s wrong and why, the next step is fixing it.

Step 3: Implement the Fix (Or Decide If It’s Worth Fixing)

SEO is about making things better. But sometimes, a fix isn’t worth the effort.

Once you’ve identified the issue, the next step is deciding:

• How do we fix it?
• Who needs to be involved? (Developers? Content teams?)
• Can we automate this to prevent future issues?

Fixing Issues the Right Way

• Automate whenever possible. Schema, redirects, and meta tags should be handled programmatically.
• Bake SEO into the process. Pre-publish checklists, CMS settings, and automated QA checks help prevent recurring issues.
• Train teams to prevent future issues. Content teams, developers, and stakeholders should be informed.
• Document everything. Track dates of fixes and monitor their impact in analytics.

For example, if a site lost traffic due to slow performance, the fix shouldn’t just be optimizing images. It should include addressing caching, removing unused scripts, and implementing a CDN.

Once the fix is implemented, monitor the impact. Did rankings and traffic recover? Or is another factor at play?

Take This Process With You: Get the Technical SEO Diagnostic Checklist

If you want a structured way to apply this to your own website, grab my free Technical SEO Diagnostic Checklist. It includes:

• A step-by-step assessment guide
• A list of tools for each diagnostic step
• Common SEO problems and how to fix them

Final Thoughts

Whether you’re dealing with an SEO crisis or conducting a routine audit, the Assess, Diagnose, Fix framework helps you approach technical SEO issues systematically.