What a WordPress attribution plugin cannot see

This is an unusual post for a product to publish. But the alternative - leaving people to discover the limitations after they have installed the plugin - is worse.

CQI Referrer Attribution is a server-side attribution tool for WordPress. Here is what it does not do, clearly stated.

It cannot see AI traffic that arrives with no referrer

The plugin classifies AI referrer traffic by reading the `Referer` HTTP header. When a user clicks through from ChatGPT, Perplexity, Claude, or another AI platform, the browser may or may not send a referrer header identifying the source.

Depending on the platform and the user's path through the AI interface, somewhere between 30% and 65% of AI tool referrals arrive with no referrer header. Those sessions are not attributable by any referrer-based tool. They land in Direct.

This is not a bug or a gap specific to this plugin. It is a property of the referrer header as a signal. No server-side tool that relies on referrer classification can attribute traffic the browser did not identify. Client-side tools have the same constraint - they read `document.referrer`, which contains the same value the server received.

What the plugin does accurately attribute is the AI referrer traffic that does carry a referrer. That is a real, measurable subset of your AI-driven traffic, and it is worth measuring. But it is a floor, not a ceiling.

It cannot track visitors across multiple sessions

Sessions in CQI Referrer Attribution are scoped to a single continuous visit. The session token is derived from an anonymised IP address and the current date. It rotates daily by design - this is what makes it possible to operate without a consent requirement in standard deployments, because the token cannot be used to identify or follow an individual over time.

As a result, if the same person visits your site from Organic Search today and from an Email link next week and converts on that second visit, those appear as two separate sessions from two separate channels. There is no cross-session journey view. This is a deliberate privacy trade-off, not an oversight.

Multi-session attribution - first-touch and last-touch at the visitor level - requires persistent cross-session identifiers, which require consent and additional infrastructure. That is out of scope for this product by design.

It is WordPress-only

The plugin is a WordPress plugin. It does not work on static sites, other CMSes, or custom PHP applications. For those environments, Refer App is the equivalent standalone product.

It cannot recover UTM parameters that were never added

UTM classification requires that your campaign links carry UTM parameters. If your email platform, paid search campaigns, or affiliate links are not tagged, the traffic arrives without the signal needed for accurate classification.

The plugin classifies what it can from referrer headers alone - a link from a known search engine domain goes to Organic Search, a link from a known social platform goes to Social Media - but paid campaigns that share a domain with their organic counterparts (Google Ads vs Google Search, for example) are indistinguishable without UTM tags. The plugin cannot infer campaign intent from a referrer domain alone.

What it does do reliably

Server-side classification of all nine channels for traffic that carries usable signals. Accurate AI Referrer attribution for traffic with identifiable referrer domains. Complete session counts regardless of ad blockers, consent state, or JavaScript failures. No client-side scripts, no third-party data sharing, no cookie consent requirement in standard deployments.

That is a useful and specific set of things. It is also an incomplete picture of the full visitor journey, by design.

If you need cross-session attribution, multi-channel funnels, or cohort analysis, you need a different tool. If you need to know where your traffic is coming from today, accurately and completely, without adding JavaScript overhead or requiring consent, this is built for that.

*CQI Referrer Attribution is a free WordPress plugin. Pro adds conversion tracking, trends, insights, content attribution, and branded reports.*