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AI Search

# Why Your Website Site Search Should Be Semantic

AB

Akshaya Balasubramaniyan

Content Lead, Keyspider

December 2022

7 min read

Semantic search is changing what users expect from the search bar on your website. As consumers are trained by Google, Siri, and Alexa to ask questions in natural language and receive direct, contextually relevant answers, they bring those same expectations to every search interaction, including the search bar on your organisation's website. If your site search returns a list of keyword-matched links in response to a natural language question, you are failing users who are now accustomed to far better.

But beyond user expectations, there is a more fundamental reason to make site search semantic: keyword search is a vocabulary lottery. It requires users to know and use the same words that appear in your content. In practice, this is an enormous ask. Users describe the same things in dozens of different ways, and the official or technical language in your documents often bears little resemblance to how ordinary people talk about the same topics.

## What Makes Search Semantic?

Semantic search uses natural language processing to understand the intent and meaning behind a query, rather than simply matching its literal words against an index. Instead of asking 'which documents contain these exact words?', a semantic search engine asks 'which documents are about the same thing this user is asking about?'.

Under the hood, this works through vector embeddings: mathematical representations of the meaning of words, phrases, and documents, positioned in a high-dimensional space where semantically similar content sits close together. When a user submits a query, it is converted to a vector representation and compared against all document vectors in the index. The closest matches are returned, regardless of whether they share any words with the query.

> A user searching for 'how do I remove my subscription' and a document titled 'Cancellation and Membership Termination Policy' share no common keywords. Semantic search recognises that they are about the same thing. Keyword search returns nothing.

## The Vocabulary Gap Problem

Every domain has a vocabulary gap: the difference between how users describe things and how content creators write about them. In retail, customers say 'trainers' and your catalogue says 'athletic footwear'. In government, citizens ask about 'getting a driver's licence' and the relevant page is titled 'Motor Vehicle Operator's Permit Application Procedure'. In healthcare, patients describe symptoms in everyday language while clinical documents use diagnostic terminology.

Keyword search has no mechanism to bridge this gap. You can manually configure synonym mappings, but this requires continuous maintenance as language evolves and content changes. Semantic search handles the vocabulary gap automatically and generalisably, without requiring a manually maintained list of synonyms for every possible variation.

- Semantic search understands that 'bin collection' and 'waste removal schedule' are the same query
- It knows 'student expelled' relates to 'suspension and exclusion appeal process'
- It recognises that 'my invoice is wrong' maps to 'billing dispute resolution'
- It handles professional, technical, and colloquial language for the same concept simultaneously
- It adapts to new language naturally, without requiring manual synonym configuration

## SEO Benefits of Semantic Search on Your Website

Semantic search improves not just your on-site user experience but also your organic search performance. Search engines like Google use semantic analysis to understand what your content is about and match it to searcher intent. By ensuring your internal search and your content strategy are both aligned to semantic principles, including comprehensive topic coverage rather than keyword stuffing, you create content that performs well both for users and for search engines.

Semantic search analytics also tell you exactly what topics your users are interested in, expressed in their own language. This is invaluable for content strategy: you can see which topics attract the most searches, which queries return poor results (indicating content gaps), and which areas of your website are effectively serving user needs versus which are being ignored.

## Semantic Search in Practice: Real Examples

### Government and Public Sector

A state government website serving millions of citizens handles queries on everything from social services to road maintenance to public health. The website was written by dozens of different departments using inconsistent terminology. Semantic search enables citizens to search in everyday language and find the relevant service or document, regardless of which department wrote it or what internal naming conventions they used.

### University and Higher Education

A university website has content from faculties, the registrar, student services, IT support, and a dozen other departments, each with its own terminology. A prospective student asking 'what marks do I need to study medicine' should find the entry requirements page, even though that page uses terms like 'ATAR', 'selection rank', and 'Year 12 prerequisites'. Semantic search makes this connection automatically.

### Corporate Knowledge Management

An enterprise with thousands of internal documents, policy manuals, and support articles needs employees to find relevant information quickly. When a new employee searches 'how long before I get paid', they should find the payroll schedule, even though that document uses terms like 'pay cycle', 'salary payment date', and 'remuneration processing'. Semantic search makes knowledge accessible to people who do not yet know the internal vocabulary.

## How to Evaluate Semantic Search Solutions

1. 1 Test with real queries that use terminology different from your content: if the engine handles these correctly, it is truly semantic
2. 2 Check how the engine handles multi-word concepts and entity recognition, not just individual keyword matching
3. 3 Verify the latency: semantic search using vector embeddings should still return results in under 200 milliseconds for a good user experience
4. 4 Understand the indexing pipeline: how quickly does new or updated content appear in search results?
5. 5 Assess the analytics: does the platform show you which queries are performing well and which are returning poor results?
6. 6 Confirm the approach to grounding for any AI answer generation features: answers should always cite source documents

Getting started

The fastest way to understand the impact of semantic search on your specific website is to run a proof of concept with your actual content. Identify your top 20 zero-results queries from your current search analytics, then test those same queries against a semantic search implementation. The difference in result quality immediately demonstrates the value of the upgrade.

Explore further

AI Search vs. Keyword Search A detailed technical and practical comparison of keyword and semantic search.
12 Must-Have Site Search Features The complete feature checklist for evaluating site search solutions.
Search Analytics as a Content Strategy Tool How search data reveals content gaps you did not know existed.
Keyspider AI Search See how Keyspider's semantic search deploys on your website.

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