Data Carnage: Fixing Google Search Console after num=100

by Martin Hayman
5 minute read

Between 10-14 Sept 2025, Google disabled the num=100 parameter that let tools (and power users) load 100 results on a single SERP page. Overnight, everyone was back to 10 results per page. Rank trackers stumbled, Google Search Console (GSC) impressions fell for most sites, not because your real visibility collapsed, but because deep-page bot-driven impressions disappeared. That means your data is now closer to user reality. Below, we look at what changed, what the evidence shows, how metrics will behave (impressions ↓, average position ↑, CTR often ↑ mechanically), and a step-by-step plan to re-baseline reporting, KPIs and client comms.

What changed and when

• Google ended support for results-per-page (&num=100). Google’s comment: the URL parameter is “not something we formally support.” → Intentional, not a bug.

• Timeline: The change surfaced 10-14 Sept 2025. Early testing showed &num=100 only worked intermittently, then stopped.

• Immediate impact for tooling: Getting Top 100 now means 10× more page requests (and 10x cost). Some vendors limited depth; many have remained quiet.

Why GSC impressions fell (and average position rose)

An impression is counted when your result is on the loaded page. For years, many trackers loaded 100 result pages, minting non-human impressions for positions 11-100. Removing num=100 stopped those deep page loads, so the inflation vanished. Result:

• Impressions ↓ – because deep bot loads have stopped.

• Average position ↑ (numerically better) – because ultra-deep impressions are no longer being seen much, the “average” shifts toward positions users actually see.

• CTR often ↑ – If clicks remain stable while impressions fall, CTR (clicks ÷ impressions) rises. Don’t celebrate; annotate.

The “Great Decoupling,” re-examined (AI and bots)

• AI Overviews (AIO) expanded across 2024-25 and correlate with lower CTR where shown. That’s a user behaviour change.
• Sept 2025 revealed a second force: measurement noise. Killing num=100 collapsed bot-inflated impressions, making the decoupling look less extreme in GSC going forward.

For a thorough walk-through of the bot-inflation theory and timelines, see Brodie Clark’s analysis.

This was not a ranking update

No algorithmic reshuffle shipped with this. If your reports look jagged, it’s due to measurement and methodology, not mass ranking loss. Tools changed how (and how deep) they collect results; Google’s action changed what gets counted in GSC.

Fix your reporting (today)

1) Annotate everything at 10th Sept 2025

Add “Reporting change: num=100 disabled” annotation to any relevant tools that allow annotations.

2) Re-baseline KPIs (fewer vanity metrics, more outcomes)

• Track page 1 keywords (count and net new)
• Track promotions to page 1 from page 2/3 (positions 11-30).
• De-emphasise impressions (for now).

3) Choose a sane tracking model (and label it clearly)

• Exact Top-10/20 (daily): the most actionable data at a sustainable cost.
• Hybrid: exact page 1 (daily) + GSC position as a directional signal for page 2+.

4) Run 11→9 sprints weekly (page 2 → page 1)

Treat positions 11-30 as opportunity; page 2 is the runway:

• Re-check intent match and fill on-page gaps
• Add internal links from relevant, high-equity pages
• Refresh content and upgrade headings/media
• Retest titles/meta for a CTR bump (especially positions 4-10)

5) Set expectations early with clients

Use plain English: “Google removed a data shortcut that inflated impressions in Google Search Console. We annotated reports, reset baselines, and doubled down on page 1 growth.” (Template below.)

Client email template example (copy/paste)

Subject: We’ve annotated your SEO dashboards (here’s why)

Hi [Name],

Last week, Google changed how it serves results. A long-used parameter that let tools load 100 results on one page was removed. That had been inflating impressions in Search Console across the industry.

What you’ll see now (from Sept 10th onward): impressions may look lower. Clicks and conversions are unaffected. Average position may improve (since deep rankings are seen less). CTR can rise mechanically because impressions fell.

What we’ve done:

• Annotated your dashboards at the change date.
• Reset baselines and focused KPIs on page-1 growth (where results happen).
• Continued exact daily tracking on page 1, with directional signals for deeper ranks.
• Started weekly “11→9” sprints to move near-wins onto page 1.

Happy to walk you through this in more detail.

FAQs (that clients or the boss might ask)

“Did our SEO performance drop?” No. You’re seeing truer data. What changed is what gets counted, not the underlying algorithm.

“Why does average position look better?” Ultra-deep impressions were removed from the equation; averages shift towards rankings people actually see.

“Our CTR jumped. Should we celebrate?” Treat it as mechanical if clicks are steady. CTR = clicks ÷ impressions; fewer impressions can inflate CTR.

What to do next

• Download the 11→9 Sprint Checklist (free) and bake the sprint into your weekly ops.
• Add the “Reporting change” annotation to your SEO tools today.
• Re-baseline your KPIs around page 1 outcomes, not top-100 archaeology.

Page 1 is where the action is. Get more of your keywords there, faster.