Quick answer
We grade a source by how close it is to the thing being measured. Google’s own documentation and status dashboards come first. Then controlled tests and peer-reviewed research. Then the established industry publications that show their method. Vendor blogs are used only for their own product behaviour or their own survey data. Forums, listicles and personality blogs are read for context but are not cited as evidence. If a claim on this site has a number attached, it traces back to one of the sources below, labelled with our evidence standard.
How we grade a source
- Primary documentation. Google Search Central, Google Business Profile Help, Google Ads Help, GA4 Help. The platform describing its own behaviour. Highest weight, labelled GOOGLE DOCUMENTED.
- Controlled tests. Published experiments that changed one variable and measured the result, ideally across many locations. Labelled CONTROLLED TEST.
- Peer-reviewed research. Papers in venues like Marketing Science, Management Science, ACM Computing Surveys and KDD. We keep citations within about ten years. Labelled INDEPENDENT RESEARCH.
- Industry surveys and publications that disclose their method: Whitespark, BrightLocal, Search Engine Land, Search Engine Journal, Moz. Labelled INDEPENDENT RESEARCH or INDUSTRY PRICING GUIDES.
- Data providers. DataForSEO for keyword volume, difficulty and SERP composition. Labelled INDUSTRY DATA.
- Our own data. Client Google Business Profile exports over a dated window, labelled DHM DATA. Our reading of that data is labelled DHM INTERPRETATION.
- Not cited as evidence: Reddit and Slack communities, Quora, aggregator listicles, and single-author opinion blogs. Useful for spotting a pattern; not proof of one.
Google’s own documentation
- Google Search Central. The authority on crawling, indexing, ranking systems and core updates. Where we source anything labelled Google Documented about organic search.
- Google Search Console Help. Index coverage, sitemaps, the Pages report, Core Web Vitals. The reference for diagnosing why a page is not indexed.
- Google Business Profile Help. The guidelines for representing a business, the local ranking factors page (relevance, distance, prominence), review policies and reinstatement.
- Google Search Status Dashboard. The official record of when a ranking or spam update started and finished, so movement can be lined up against a real date.
- Google Ads Help. Bidding mechanics, Quality Score, match types. Used on the paid-ads pages.
- Google Analytics 4 Help. Events, conversions, explorations and data retention, for measuring what a visit actually did.
Local search research and surveys
- Whitespark, Local Search Ranking Factors. The annual practitioner survey behind the weight estimates we quote: proximity, profile signals, review signals, on-page. We cite the method, not a single number as gospel.
- BrightLocal research. The Local Consumer Review Survey and related studies: how consumers use reviews, the four-star threshold, response expectations.
- Sterling Sky and the Local Search Forum. Practitioner testing on suspensions, filtering, and profile behaviour, often the first to document a change.
- DataForSEO. Keyword volume and difficulty, and SERP composition by location, which is how we show that local pack results change point to point.
Industry publications we trust
- Search Engine Land. Daily search news with named reporters and linked primary sources. Our reference for AI Overview prevalence and update reporting.
- Search Engine Journal. Deep explainers and aggregated algorithmic reporting across search and multi-channel.
- Moz Blog and Beginner’s Guide to SEO. The reference introduction to SEO concepts, and the origin of domain-authority-style metrics.
- Ahrefs Blog. Technical SEO method, keyword research process, and large-scale studies of search behaviour.
- Semrush Blog and Academy. Search-intent frameworks, competitive analysis and backlink auditing method.
- Backlinko. Simplified, well-illustrated deep dives on link building and click-through behaviour, with the data shown.
- SparkToro Blog. Audience research method and zero-click search tracking, useful for framing what a search visit is worth now.
Technical, analytics and CRO
- Simo Ahava’s blog. The reference for technical Google Tag Manager and measurement implementation.
- Microsoft Clarity documentation. Free session recordings, heatmaps and click tracking. We run Clarity on this site.
- Screaming Frog SEO Spider. The crawl tool and its documentation, for site architecture, redirect chains and metadata audits.
- CXL (Conversion XL). Data-validated conversion optimization method and user-testing logs.
- Hotjar guides. Behaviour analytics setup and how to read heatmaps and session recordings without over-reading them.
Platform documentation
Used where a page touches paid or social, for the platform’s own rules and specs rather than commentary about them.
- Meta for Business Help Center. Pixel and Conversions API setup, Custom Audiences, ad policy.
- LinkedIn Marketing Solutions. B2B ad specs and targeting, for commercial and professional-service accounts.
- Microsoft Advertising Help. Bing search network setup and reach, for accounts that run it alongside Google Ads.
- YouTube Creator resources and Pinterest Business Help. Platform mechanics for the visual and video channels, when a client’s work is genuinely visual.
Academic venues we cite from
Where our peer-reviewed citations come from. We keep them within about ten years and lead with newer data where it exists.
- ACM SIGKDD and the KDD proceedings: the venue for the Generative Engine Optimization work we cite on what gets quoted in AI answers.
- Marketing Science and Management Science: review-response effects, reputation systems, paid-search incrementality.
- ACM Computing Surveys: entity resolution, the computing problem behind name-address-phone consistency.
- Annual Review of Economics: reputation and feedback systems in online platform markets.