The 90% Rule - Keeping Keywords Relevant

How do you decide which keywords are appropriate?  Should you include every conceivable word which might be relevant to an image or video, or should you try to keep the number of keywords to a bare minimum?  The answer is the 90% rule.

When undertaking keywording, there is a sure way to unwanted cost and a little madness: try to create the perfect set of keywords.  Apart from the impossibility of attaining perfection itself, the process of trying to reach that goal is normally extremely time consuming as well as pointless.

Instead, attempt to reach a 90% confidence level for each keyword and for the set as a whole.  This is not a scientifically-measurable percentage, but more an acknowledgement that taking the acceptable level back from perfection is an acceptable and attainable result.

So the aim of the exercise is to save time, but also to stop the number of keywords becoming so enormous, and the keywords so tenuous, that you can find virtually every image by using virtually any keyword.  The more focused on the essence of the image/video the keywords are, the more effective research will be.

When an archive is small, this problem may seem non-existent, but for companies such as Getty Images, with enormous archives, neglecting this problem is extremely commercially damaging as research will drag in thousands of irrelevant images.

Consider this application of the 90% rule:  In a picture of a couple kissing, you can justifiably argue that a keyword such as "romance" would be expected by 90% of researchers.  Now take a picture of a couple holding hands and walking down the street with shopping bags in their hand, looking a bit glum.  Some people might think that because the couple are holding hands that the word "romance" is still appropriate.  But it can be argued that at least 90% of researchers would be disappointed to find such an image with that keyword.  By the same token, at least 90% of researchers would be happy to find that image with the keyword "shopping".

It is not that this confidence level will find the right image every time, more that it will stop irrelevant padded-out search results.

Likewise, if the number of keywords is too small you are short changing researchers.  In that case, consider if there is another word you can add which 90% of researchers would be happy to use.  So if the word shopping was not used in our example that would be poor keywording as more than 90% of researchers would be likely to expect it.

As mentioned, this is not a matter of science, more of judgment, but it can help you focus you efforts on getting an appropriate set of keywords.

One caveat though is that keywords destined for third parties such as Getty Images, Corbis or Alamy, should always be 100% in compliance with their standards and conventions.