In recent weeks, several SEO-tool vendors and analysts have picked up on a subtle but significant shift from Google in how search engine results pages (SERPs) are served and how third-party tools can collect them. When working in the fast-moving world of digital marketing, it’s essential to understand what’s changed, how it impacts data collection and rank-tracking, and what you should do about it.

What’s going on?

Two main developments have emerged:

1. Removal of the “&num=100” parameter
   Google appears to have disabled or significantly limited the &num=100 query-parameter which previously enabled retrieval of 100 results in a single SERP request (Search Engine Journal). This parameter has long helped rank-tracker and SERP-monitoring tools by allowing them to fetch up to 100 results in one go. With its removal, those tools now face more complexity and cost. According to Semrush, Google quietly removed this option for users to view 100 results on a single page with no prior warning.

2. Impact on rank-tracking tools and impression metrics
   The change has led to noticeable drops in desktop impressions and changes in average position metrics for some Google Search Console accounts, particularly since around 10 September 2025. The theory emerging is that when tools were able to scrape 100-result pages via &num=100, they generated inflated impression counts because they accessed many more positions than regular users would. With the parameter removed, those “extra” impressions disappear — and average position may therefore appear to improve (Search Engine Journal).

Why this matters for agencies and marketers

For digital agencies (and their clients), in-house SEO functions and account directors, the ramifications are immediate:

• Rank-tracking coverage changes: If a tool can no longer fetch positions 1–100 easily, visibility into competition and long-tail keyword performance may suffer. For example, AccuRanker responded by shifting to daily tracking of the Top 30 results, and bi-weekly tracking of the Top 100 instead of daily, to adapt to the change (accuranker.com).

• Historical data comparability: When a methodological change like this hits, year-on-year or month-on-month comparisons can be misleading. Drops in “impressions” may reflect the change in collection method rather than a drop in organic visibility or performance.

• Tool reliability and transparency: Vendors must adapt their infrastructure and clearly communicate any data-collection changes. Semrush emphasised that its core metrics (Top 10, Top 20) remain unaffected by Google’s shift, with other vendors attempting to provide the full 100 SERP results through a hefty subscription increase.

• Focus on meaningful positions: The first page of Google remains where the majority of clicks lie. As Ahrefs points out, while extended visibility beyond the first page remains useful, the core value still resides with positions 1–10. They estimate 97% of clicks through to websites occur in the top 10 results, rendering this change ineffective to meaningful performance reporting.

What should you do?

As mentioned above, these changes are more significant in terms of the processes you currently follow for your SEO activity, rather than the results themselves. Here are practical steps you can implement across your accounts and dashboards to adjust your processes:

1. Audit your tool-vendor methodology
   Ask your rank-tracking provider how they’re handling the absence of &num=100. Are they switching to multiple requests? Are there increased latency or coverage gaps? Do their historical graphs reflect a methodology change?
   Consider adding insights to your reports noting that “data collection methodology changed in September 2025” so that stakeholders don’t misinterpret any sudden shifts.

2. Re-benchmark rankings and impression trends
   Since around 10th September you may be operating off a new baseline in your data. Analyse your Google Search Console data for week-over-week shifts post-change. If you see decreased impressions but steady clicks, don’t immediately conclude that Organic performance is worse — it may simply be the parameter change at work (Search Engine Journal).

3. Re-prioritise reporting metrics
   Given the tool-collection challenge, lean into metrics that are robust: Top 10 and Top 20 rankings, click-through rate (CTR), and conversions. Less reliable metrics to wind-down on include large-scale Top 100 coverage – unless ,your vendor’s methodology is crystal clear.
   As an agency, you may want to shift client conversations away from “we track position 78” towards “are we in the first 3 pages and how is visibility trending over time?”.

4. Update your strategic narrative
   Any sudden shifts in average position or impressions in your monthly briefs should be contextualised. Explain that Google changed how SERPs are served and how tools collect data — so changes may reflect measurement rather than performance. This protects your narrative credibility.

5. Stay alert for further changes
   Both Ahrefs and Search Engine Journal note that Google hasn’t publicly commented on whether this is a permanent shift or part of an experiment. As always in SEO, adaptability and measurement methodology clarity are key.

In summary

Google’s adjustment to how SERPs are paginated and how the &num=100 parameter is handled may not grab headlines like a core algorithm update — but for account directors and SEO teams it is significant. It shifts how rank-tracking tools work, how historical comparisons must be treated, and how you explain performance changes to clients.

For your team, the most important takeaway is this: the first page still matters most — focus on the metrics that drive results, keep vendor methodology transparent, and ensure your reports tell the full story. By staying ahead of the measurement shift, you’ll maintain credibility and continue to deliver meaningful insights.