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Key Stage 2 computing · Information technology

KS2 using search engines: how results are chosen and ranked

Searching online is one of the most common things children do with technology, yet few of them know how a search engine decides what to show. In Key Stage 2, children learn to choose effective keywords, refine a search that isn’t working, and understand that results are selected and ranked by a computer program, so the first result is not automatically the best or the most truthful.

Search engines and ranked results, explained

A search engine is a web service that helps people find pages. It doesn’t search the whole web live each time you type. Instead, it has already visited huge numbers of pages with automated programs, collected information about them into an enormous index, and uses that index to find pages that match your words. Children usually meet this as a simple idea: the search engine has a giant list of pages and picks the ones that seem to fit your question.

Which pages come first is decided by ranking. The ranking uses an algorithm, a set of rules that scores pages in many ways, such as how well the page matches the words you typed, how many other pages link to it and, for some searches, where you are. Search engines do not share the full details, so children are taught the general idea rather than a formula. Results can also include adverts, which are labelled as such but can look like the other results, and which appear because someone has paid for them.

Searching well is a skill that needs practice. Children learn to choose a few precise keywords instead of typing a whole question, to add or remove words when the first results are too broad or too narrow, and to use a search for images, news or other types of result when those suit the task. Some schools also teach putting a phrase in quotation marks, which asks the search engine to look for those words together. Filters and safe search settings are often used on school devices.

Searching does not finish when the results appear. Children are taught to look at the address and the short snippet before they click, to skim a page for the information they need and to compare more than one source. This leads straight into being discerning about what they find, which has its own guide. The curriculum asks children to appreciate how results are selected and ranked, so they can see that a search engine is a tool with choices built into it. Some search engines now show an automatically written summary above the results. It can be wrong, so it needs the same checking as any other source.

Words your child will hear

Search engine
A web service that finds pages matching the words you type.
Keyword
An important word used in a search, such as “barn owl diet”.
Index
A huge list of pages that a search engine has collected information about.
Ranking
The order in which a search engine puts the results.
Sponsored result
An advert shown among the results because someone paid for it.
Refine
Change or add keywords to make a search more precise.
Filter
A setting that limits results, for example to images or to a recent date.

What the National Curriculum says

The programme of study for Key Stage 2 says:

  • Pupils should be taught to use search technologies effectively, appreciate how results are selected and ranked, and be discerning in evaluating digital content
  • Aim: pupils can evaluate and apply information technology, including new or unfamiliar technologies, analytically to solve problems.

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

A worked example: finding out what barn owls eat

A child wants to know what barn owls eat. Their first search for owls gives pages about owl cafés, toys and many types of owl. How could they search better?

  1. Look at why the search didn’t work. The single word owls is too broad: the search engine has no idea which owl, or which fact, is wanted.
  2. Choose better keywords. The important ideas are the kind of owl and the thing to find out. Try barn owl diet. Leave out small words such as what and do.
  3. Read the results with care. Some of the first results may be labelled as adverts or sponsored, so skip those. Look at each address and snippet and choose a page from a wildlife charity, museum or library collection rather than a page full of advertising.
  4. Compare. Open a second page and check that it gives the same main facts, for example that barn owls mostly eat small mammals such as voles, mice and shrews.
  5. If more help is needed, refine again: add the word UK, or use image search to see pictures of pellets, which contain the bones of the animals the owl has eaten.

Searching for barn owl diet, skipping the adverts and checking two pages gives the answer: barn owls mostly eat small mammals such as voles, mice and shrews.

Common mistakes and how to help

“The first result is the best or most accurate”

Results at the top look important, and children trust the computer’s order. Ranking weighs up many things, and a high place does not guarantee that a page is accurate.

What helps: Ask your child to open three results and say which one they trust most and why. Notice that the best page may not be first.

Not noticing adverts in the results

Sponsored results can look almost the same as other results. A small label is easy to miss.

What helps: Search for something you could buy and find the label together. Explain that these results are there because a company paid.

Typing a long question and giving up when it fails

Children are used to asking people and voice assistants in full sentences. The search engine still works best with a few strong keywords.

What helps: Show how to pick the two or three most important words in the question, then add or swap one word at a time.

Believing the search engine searches the live web, or knows the answer

It feels as though the computer is thinking about your question. In fact it is matching your words against an index that was built earlier.

What helps: Describe it as a very fast librarian with a giant catalogue who points you to the books, but doesn’t guarantee that the books are right.

How to help at home

  • Search race. Choose a question, such as how tall the tallest tree in Britain is, and see who can find the answer in fewer searches. Compare the keywords you each tried and talk about which worked best.
  • Find the adverts. Run a search together and point out which results are adverts and which are not. Ask your child why a company would pay to appear at the top.
  • Two-source rule. Make it a habit that no fact gets used until it has been found in two different places. This turns searching into checking, and it is a good habit for homework too.
  • Change one word. Search for the same topic with slightly different keywords and see how the results change. Children quickly learn that wording matters.
  • Use safe settings. Check that safe search and any parental controls are switched on for devices your child uses, and stay close by when they search at this age.

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