and Google’s ‘Safe Search STRICT’ technology is a good idea. It is “an educational boolean search tool” that graphically depicts boolean or basic web searches. Users drag blocks depicting elements of search parameters (OR, AND or NOT) onto a display area and choose to a web (default), news or image search. Four result links are then displayed under the block display area.

There are four pages each with four results available within Boolify, and a link to ‘more results’ that opens Google in a new window with ‘safe search on’ for regular searches and ‘strict safe search on’ for image searches.

The search page

The idea is that graphical ways of thinking about boolean searches make them easier for children to understand. It is aimed at mainly elementary and middle school children. The website states:

Search results are presented through Google’s “Safe Search STRICT” technology, so we’re confident that the results your students receive are safe.

***EDIT: The above quote no longer appears on Boolify’s ‘About’ page as the content of the page has been changed to reflect the content of this post and to link here. My thanks to Dave Crusoe from for pointing this out.***

Boolify is a beta release and the work will be evaluated mid 2008 to see how well it it is going.

It is a good idea. What does ‘safe’ mean though?

Google’s ‘safe search’ is a fast and accurate (optional) filter system that stops so called ‘adult sites’ from appearing on search results. Google states:

Many users prefer not to have adult sites included in their search results (especially if their kids use the same computer). Google’s SafeSearch screens for sites that contain this type of information and eliminates them from search results. While no filter is 100% accurate, Google’s filter uses advanced technology to check keywords, phrases, and URLs.

Did you notice a discrepancy? Boolify says results are “safe” but Google says that “no filter is 100% accurate.” I trust Google on this one.

Boolify are correct in that they are using a strong filter that works well. However, a filter can be imagined as ice on water; it covers an area, looks firm, but is thicker in some places than others, and may still be dangerous. This is because the filter scans web pages for blacklisted keywords, phrases, and URLs. If it finds any of these the search result is withheld. The ice stays safe to walk on. It is possible though that content that could be described as ‘adult’ is not nicely labeled as such. For instance an ‘adult’ image in an otherwise ‘safe’ page might not be helpfully labeled to match a filter’s blacklists. The ice here becomes thin, as a ‘safe’ keyword in a ‘safe’ search may just possibly return unwanted results.

The percentage of unwanted information getting through may be small, but we should understand the tools we use every day. We should know where they excel and where they are weak.

Below is an example of such a situation (please note that I do not imply and criticism of Boolify or Google. They are both good services! The example is used to highlight the weakness of filters in general in order to aid understanding):

I enter the search term ‘xray’ in Boolify and select to search images. Four images are displayed, they are relevant and good. All four of the search result screens (each with four images) that display within Boolify return similar results. Great! I click ‘more results’ and the first screen of full Google search results open on a Google page in a new window. ‘Strict safe search’ is already set, just as within Boolify. Good. Results look similar again. I click ‘Next’ and all is well. I click ‘Next’ again and see two images that have fallen through the filter’s net.

Gooooooooogle Next

One is what looks like a cola bottle firmly lodged somewhere the manufacturers probably never intended it should go, from a website I would not want a young child to stumble upon. The title of the image is ‘Interesting X-Ray’. Of course neither of those words would match keywords or phrases in a filter’s blacklists. The other is labeled ‘X-ray it looks very real,…’ and it turns out to be an image by an artist called Wim Delvoye from a series of artworks called ‘Sex-rays’ (not what I searched for, but the image was not labeled clearly). The link opens a forum where people are discussing how the image was made and if it is an actual xray or not. Not what I want a primary a primary age child to see in a lesson, anyway.

The moral of the story is don’t assume ‘safe’ has the same definition for you as it does to filtering software. Content filters cannot see and judge the appropriateness of images as you can… yet. So check search results beforehand if planning to search the web with older children. Younger children could learn search skills by searching for clip art within a word processing program. Or use Yahoo kids search or the BBC CBBC Find facility. These are both checked regularly and list only approved sites. However, best check first!


4 Responses to and Google’s ‘Safe Search STRICT’ technology

  1. Dave Crusoe says:


    I really appreciate your digging on this issue. I’ll correct the information page to include this blog post, which is an exceptional look at filtering safety.


  2. Robert Saunders says:

    Thank you very much!

  3. […] Search STRICT” technology. However, no filtering technology is 100% secure, as this blog posting astutely points […]

  4. […] technology. There are two important caveats: a) no filtering technology is 100% secure, as this blog posting astutely points out and 2) we are unable to control or modify the results that we provide, beyond […]

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