Category Citation Index
This index ranks the domains and individual pages explicitly cited across published Walk-In Tubs consensus studies from Aging in Place Index. The dataset covers research conducted across seven AI platforms and multiple buyer needs.
Calculation version 1 is methodology metadata, not a product version or score.
The Walk-In Tubs Citation Index measures which web sources were explicitly cited during the AI research used to produce Aging in Place Index consensus studies. It is a descriptive record of observed citation behavior, not an evaluation of product quality or a source-authority score.
This snapshot includes 15 published Walk-In Tubs studies, 7 AI platforms, and the valid research responses recorded in the published study snapshots. The studies cover distinct Walk-In Tubs buyer needs in the United States.
The measured AI platforms are:
The primary unit is a normalized URL cited in a valid AI research response. Domain-level results are aggregations of those URL records.
A normalized URL may contribute no more than one Citation Occurrence within a single valid response. It may contribute another occurrence when cited in another response, study, or platform. Multiple different URLs from the same domain may each contribute an occurrence within the same response.
Citation Share is a domain’s or URL’s Citation Occurrences divided by all Citation Occurrences in the snapshot. It is not Response Coverage. Rank does not use Citation Share; the percentage is a descriptive share of observed citations.
A domain or URL is counted no more than once per valid response when calculating Citing Responses and Response Coverage.
Hostnames are lowercased, www. is removed when it does not represent a separate property, fragments and known tracking parameters are stripped, default ports are removed, and trailing-slash behavior is standardized. Original cited URLs are preserved in the underlying record.
Google grounding redirect URLs and other platform-generated redirect wrappers are resolved to the final publisher URL whenever possible. Unresolved wrappers are retained in the audit file but excluded from publisher-domain rankings because the wrapper platform is not the underlying source.
Domains are grouped using the registrable domain. Subdomains are generally merged into the registrable domain unless a subdomain represents a materially separate publishing entity that the methodology intentionally preserves.
Every observed citation is retained as evidence of what the AI platform returned, even when the destination is later broken or unavailable. Destination availability is not validated in this snapshot (WIT-2026-08-V1). A later snapshot may report Live, Redirected, Broken, or Unresolved status after an automated check. A valid HTTP response would not establish that a page’s claims are accurate.
A response is valid only when it is complete, the required schema can be parsed, the study and platform are identifiable, the response can be associated with its correct research record, and the citation data is not corrupted.
Failed platform calls, empty responses, truncated responses, malformed structured data, duplicate response records, and responses that cannot be associated with a valid study record are excluded from the denominator. A failed response is never replaced with an assumed zero-citation response.
Company-owned is assigned only when the cited registrable domain matches the official domain of a qualified company evaluated in the research (including that company’s known parent or subsidiary identity in the research entity table). Independent, in this column, means the source is not that evaluated-company domain. A commercial publisher is not Company-owned merely because it is a business. Mixed is used when a domain contains both classifications in different study contexts. Unclear is used when ownership could not be established with sufficient confidence. Source Relationship is not used in ranking or Citation Rating.
Publisher class is a separate layer from Source Relationship. Company-owned uses the same evaluated-company rule. Remaining domains are classified as Independent publisher, Government / nonprofit, Community / UGC, or Other using a curated domain table plus heuristics such as .gov/.mil hosts. Unclassified remainder is Other, not Independent publisher. The evidence-environment mix is occurrence-weighted Citation Share across those five classes. It is not a count of domains and does not measure influence or quality.
Domain and URL rankings are ordered first by Citation Occurrences, then by Citing Responses, study coverage, platform coverage, and alphabetical name as the final tie-breaker. Overall Rank is the snapshot rank and is not renumbered when a visitor filters or paginates.
Explicit citation frequency does not reveal every source a platform retrieved or used internally. AI platforms have different citation interfaces, retrieval systems, and source-display behavior. A citation does not necessarily represent endorsement or positive sentiment. A highly cited source may contain inaccurate, outdated, duplicated, or company-supplied information. These results are a snapshot and may change when platforms, search indexes, products, pages, or source environments change. This index is not a product ranking and should not be used to determine which Walk-In Tubs option is best for an individual consumer.
Aging in Place Index and LLM Authority Index are affiliated publications. Aging in Place Index produces the underlying consensus studies, while LLM Authority Index aggregates and analyzes the citation records. Companies cannot purchase inclusion, ranking position, or favorable treatment in either index.
These figures describe how Citation Occurrences cluster across unique URLs and domains in this snapshot. Frequency is not influence, authority, quality, endorsement, or causation.
2.189
Average Citation Occurrences per unique URL
20.48%
Unique URLs cited by multiple platforms
53.56%
Top 10 Domain Citation Share
72.69%
Top 25 Domain Citation Share
84.37%
Top 50 Domain Citation Share
8.90%
Top 10 URL Citation Share
16.81%
Top 25 URL Citation Share
Each cell is the number of normalized URLs cited by both platforms. Diagonal cells show each platform's total unique URLs.
Swipe sideways to see all columns.
| Platform | Anthropic | DeepSeek | Grok | Kimi | OpenAI | Perplexity | |
|---|---|---|---|---|---|---|---|
| Anthropic | 530 | 23 | 36 | 90 | 36 | 116 | 55 |
| DeepSeek | 23 | 124 | 26 | 31 | 42 | 29 | 32 |
| 36 | 26 | 255 | 29 | 23 | 25 | 24 | |
| Grok | 90 | 31 | 29 | 133 | 34 | 65 | 37 |
| Kimi | 36 | 42 | 23 | 34 | 158 | 34 | 25 |
| OpenAI | 116 | 29 | 25 | 65 | 34 | 328 | 47 |
| Perplexity | 55 | 32 | 24 | 37 | 25 | 47 | 132 |
How to cite
Source: LLM Authority Index - Walk-In Tubs AI Citation Index…
