Stem terms not Head terms: Latent semantic indexing

Keyword research has been the foundation of search engine optimisation plans for over a decade. The identification of high frequency search terms has driven many clients to expect results in terms of rank rather than ROI.

How many times has a client called to ask what can be done to get term X into first position in Google ?

How many times do you ask the client why they want that particular term in 1st place ?

The most often reason given (following a stunned silence) is that it is “clearly an important term for their business, it drives a lot of traffic”. Now, traffic may be important if you are running an affiliate site, or a business running advertising, where your revenue is governed by clicks. However, driving a lot of traffic does not equate to driving a lot of sales on eCom sites, or service industries or sites where the content simply does not match term X.

These terms are often referred to as ‘vanity terms’ or ‘glamour terms’. The keywords that the business owners ‘believe’ are important to their business when the truth in the data shows it is often the longer tail terms, brand traffic or other channels in combination that actually drive the sale.

The industry has fueled mis-understanding by calling short, highly searched keywords ‘head terms’. The phrase ‘head term’ carries an implication that the keyword phrase itself should be found at the top of search results.

…so we have a situation here…

Businesses are calling for ‘vanity terms’, the search industry is confusing matters further by referring to short highly searched phrases as ‘head terms’ as if it was valid that either should be ranked highly…

For example:

A small estate agency on the Isle of Man could get thousands of visitors per day if it were at the top of Google for the term ‘houses for sale’.

However, it would be much better for the estate agent to be at the top of Google for the phrase ‘houses for sale in the Isle of Man’ or even ‘houses Isle of Man’. Neither of those terms have huge search volumes, but both are imperative for an estate agent based on the Isle of Man selling houses! Visitors arriving on their site are pre-qualified and much more likely to make an inquiry.

For illustration, here’s a list of the terms of real importance to our fictitious agent

  • houses for sale in Douglas
  • houses for sale in Castletown
  • houses for sale in Peel
  • houses for sale in Ramsey

and the long tail might be:

  • 2 bed houses for sale in Douglas with garden
  • 4 bedroom houses for sale in Ramsey with garage

Rather than confuse clients by calling the keywords ‘houses for sale’ the head term, a much more accurate terminology is concept of word stems.

Key phrase Stems not Head Terms

In linguistics, a stem is the part of the word that never changes when considering the various forms of the word. For our purposes, a key phrase can been seen as a compound word, or extended stem about which we build the long tail tail terms.

In the example above, the phrase ‘houses for sale‘ becomes the stem phrase.

We can then build variants around this stem, to get the longer tail terms that are important to the business.

By talking about ‘houses for sale’ as a key phrase stem, there is no longer an implicit expectation for the ‘stem’ to reach number one in Google. It is much clearer that this is the building block around which we can optimise the site.

If we revert to talking about ‘house for sale’ as a head term, then you immediately re-introduce the idea that it is in some way important for this phrase to be at the top.

Head Term implies top and important

Stem Term implies simply a building block

As SEOs, we must explain the importance of the long tail and the concept of LSI to our clients.

At the very beginning, we should refer to words essential to the long tail search, as ‘key phrase stems’ or ‘stem terms’ instead of confusing a client using the phrase ‘head terms’.

Stems and Semantic Indexing

Exact matching terms (either on page or off page) are becoming less important over time and indeed, if over-used, exact matching terms can be detrimental to a site’ performance. Exact matching anchor is widely acknowledged as the target of the Google Penguin updates – repeated anchor text is easily identified by an algorithm.

As algorithms improve, more sophisticated connections are analysed to determine the latent semantic content of sites. Content, context and connections all play their part in deciding the relevance of a site to a search query.

By thinking in terms of stems, you change the way you think about connections too. A stem is a building block, from which ideas can grow and flow. Ideally, the stem is the distilled essence of the business, the idea behind the search term rather than the search term itself. There is often no need for the stem phrase to rank highly for a site to be successful.

In our example, the term ‘houses for sale’ may have enormous search volume. For a real estate business in the Isle of Man, enormous search volume might sound highly attractive.

Ask yourself: Who makes the agent think this way?

Are you surprised that after they read your report calling ‘houses for sale’ a ‘head term’ with 3,000 searches per day, that they believe they should rank 1st for this phrase now?

If you’d explained that the ‘stem phrase’ for their business was ‘houses for sale’ and the important converting long tail terms were built around this stem, then your client is more likely to understand why ranking for the term ‘houses for sale’ in isolation is simply pointless…

They’d also see that ‘houses for sale in the Isle of Man’ was actually the key phrase for their business.

To bake your noodle, the longer tail terms are actually the ‘head terms’ for most businesses!

The short tail phrases are the ‘stems’ around which longer tail phrases, semantic connections and ultimately ROI and a successful business is built.

PPC is different

Most PPC managers will know that AdGroups containing exact match keywords with high conversion rates are a good way to limit bidding costs and keep an account under control. The trouble is, converting longer tail variants may have never been seen before and are therefore unknown – adding exact match long tail keywords to a campaign is near impossible to achieve.
A good summary of the issues facing PPC when selecting exact match terms are discussed here

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