Reference library

Study

Original research: correlation studies, clickstream analysis, click-through benchmarks and industry surveys. Check the methodology before you quote the headline.

22 references · 2 canonical · 22 free · Intermediate / Beginner / Advanced

TitleAuthor / publisherYearLevelCost
2024 Zero-Click Search StudyCanon
Clickstream-based analysis finding that for every 1,000 Google searches only about 360 clicks reach the open web in the US and about 374 in the EU, with the remainder ending in no click or a click to a Google-owned property.
sparktoro.com
Rand Fishkin2024IntermediateFree
We Analyzed 4 Million Google Search Results: Organic CTRCanon
Widely cited organic click-through-rate study by search position, including the effect of title length, question titles and power words on CTR.
backlinko.com
Brian DeanIntermediateFree
63% of Websites Receive AI Traffic (Study of 3,000 Sites)
Analysis of referral traffic from AI assistants and answer engines across thousands of sites, quantifying how much measurable traffic AI surfaces currently send.
ahrefs.com
AhrefsIntermediateFree
96.55% of Content Gets No Traffic from Google
Large-scale study of pages in the Ahrefs index showing the extreme skew of organic traffic distribution and the correlation between referring domains and any traffic at all.
ahrefs.com
Ahrefs2023IntermediateFree
Advanced Web Ranking Google Organic CTR Study
Regularly refreshed CTR curves segmented by position, device, country, query length and SERP feature presence, drawn from a large Search Console sample.
advancedwebranking.com
Advanced Web RankingIntermediateFree
Ahrefs SEO Statistics
Continuously updated compilation of sourced SEO statistics drawn from Ahrefs' own studies and third-party research, useful as a citation index rather than as primary research.
ahrefs.com
AhrefsBeginnerFree
AI Overviews Reduce Clicks by 34.5%
Ahrefs study comparing average CTR for top-ranking pages on queries with and without an AI Overview, one of the most-cited quantifications of AI Overview click loss.
ahrefs.com
AhrefsIntermediateFree
BrightEdge Research Reports
Enterprise-panel research on channel share, SERP feature prevalence and AI Overview behaviour, drawn from BrightEdge's Data Cube of customer sites.
brightedge.com
BrightEdgeIntermediateFree
BrightLocal Local Consumer Review Survey
The longest-running annual consumer survey on how people use online reviews when choosing local businesses, covering review volume, recency, star-rating thresholds and response expectations.
brightlocal.com
BrightLocalBeginnerFree
Content Marketing Institute Research
Annual B2B and B2C content marketing benchmarks, budgets and trends surveys, the long-standing reference for content team staffing and investment norms.
contentmarketinginstitute.com
Content Marketing InstituteBeginnerFree
Do People Click on Links in Google AI Summaries?
Independent behavioural study of a representative US panel finding users are less likely to click any result when an AI summary is present. Valuable as non-vendor evidence on AI Overview click behaviour.
pewresearch.org
Pew Research Center2025IntermediateFree
Moz Search Ranking Factors
Moz's long-running ranking factors resource, historically built from practitioner surveys and correlation analysis. The reference point for how the industry has framed ranking factors since 2005.
moz.com
MozIntermediateFree
Moz: Local Search Ranking Factors
Moz's explainer and survey-derived summary of the signals that influence local pack and localised organic rankings.
moz.com
MozIntermediateFree
New Research: Google Search Grew 20%+ in 2024; Receives ~373X More Searches Than ChatGPT
Clickstream analysis quantifying Google search volume growth against ChatGPT usage, widely cited as a counterweight to predictions of rapid search volume decline.
sparktoro.com
Rand FishkinIntermediateFree
Search Engine Journal State of SEO Report
Annual practitioner survey covering budgets, team structures, tooling, priorities and the perceived impact of algorithm and AI-search changes.
searchenginejournal.com
Search Engine JournalBeginnerFree
The 2024 Web Almanac
The full 2024 edition of HTTP Archive's annual state of the web report, spanning performance, markup, media, security, CMS, accessibility and SEO chapters.
almanac.httparchive.org
HTTP Archive2024AdvancedFree
The Web Almanac — SEO Chapter
Annual, peer-reviewed analysis of SEO implementation across millions of real websites, measuring adoption of canonical tags, structured data, hreflang, robots directives and rendering patterns.
almanac.httparchive.org
HTTP ArchiveAdvancedFree
We Analyzed 11.8 Million Google Search Results
Correlation study across millions of results examining backlinks, content length, page speed, HTTPS, schema and other factors against ranking position. Correlational, not causal.
backlinko.com
Brian DeanIntermediateFree
We Studied 200,000 AI Overviews
Large-sample analysis of AI Overview appearance by query type, length, intent and citation source, one of the primary datasets on which AI Overview optimisation advice is based.
semrush.com
SemrushIntermediateFree
We Studied the Impact of AI Search on SEO Traffic
Semrush research quantifying how AI search surfaces change organic traffic patterns and the relative value of visits arriving from AI assistants.
semrush.com
SemrushIntermediateFree
Whitespark Local Search Ranking Factors Report
Annual expert survey ranking the relative importance of local pack and local organic ranking factors, including Google Business Profile signals, reviews, citations and links.
whitespark.ca
WhitesparkIntermediateFree
Why (Almost) Everything You Knew About Google CTR Is No Longer Valid
SISTRIX's large-scale CTR analysis showing how SERP features, query intent and result layout distort the classic position-to-CTR curve.
sistrix.com
SISTRIXIntermediateFree

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