1. Empty searches
Amazing numbers of people just click the search button or press Return
when the cursor is in the search field. So the search engine gets
an empty query, which is usually treated as a search failure.
What to do: either chose a search engine which brings
up a helpful search page when the search is empty, or make sure
that you have wording on your no-matches
page to explain what is going on.
2. Wrong Scope (trying to search the whole Web)
Whether it's a site, Intranet or small portal, your search engine
covers only the topics on your site, not the entire Web. For example,
searching for shot put on a site about medieval art is just
as useless as searching for marginalia on a sports portal!
Despite this, people often see the search field or button, and think
they're getting a webwide search engine. If you look in your search
logs, you'll see the wide variety of searches which clearly are not
What to do: Several search engines provide versions with
options to search the entire web, as well as the local site or portal.
In any case, the no-matches page
should explain the scope of the site and explain what materials
the search index covers.
3. Vocabulary Mismatch
Searches containing terms which are too specific, too general or
just not used. For example, on a medical site, someone searching for
doctor may need to look for physician; a horse site
may talk about Paso Finos instead of walking horses; and
a beginning web design portal may not include any sites that get into
details on onblur tags, though they may have some links to
What to do
Some search engines perform linguistic stemming -- they
search for several forms of a word instead of just the exact match.
For example, a search for run might also find running,
runs, ran, or runner; a search for goose might
also look for geese. This makes it more likely that a search
will find a match, but must be implemented carefully so it doesn't
display inappropriate matches at the top of the results list. Note
that multilingual sites must be very careful in implementing the
correct stemming algorithm for each page's languages, or they may
return some very odd results.
Adding metadata to pages can help match search words, especially
for broader and narrower terms. If you have pages describing DSL
and cable modems but never use the word broadband,
adding that term to the META Keywords tag content will allow the
search engine to find those pages
Search engines may allow search administrators to set up synonym
lists or thesari to provide appropriate alternate terms.
For direct synonyms, such as urticaria as the technical
term for hives, it's appropriate to simply add that
to the query. For less obvious equivalents, such as red for
crimson, and for broader and narrower terms, the search engine
should display them and allow the searcher to click on them rather
than typing them in.
4. Spelling Mistakes
People make mistakes in spelling all the time. For simple typos,
log file analysis shows that searchers will re-enter the word correctly.
However, they often are unable to remember unfamiliar terms such as
diseases, product codes, and names in general.
What to do
- Synonym lists (described above) can help with common
misspellings of important words on a site -- the engine can simply
translate the bad spelling to the correct version and continue.
- A spellchecker can provide a list of correctly-spelled
words, allowing searchers to switch to the right spelling.
Information Retrieval theorists have come up with some clever solutions
to spelling errors, but they can be frustrating to users unless
presented properly. Be careful when implementing a search with fuzzy
matching: use usability testing and search logs to track whether
the results are substantially better than exact matching.
- Fuzzy matching techniques try to reduce words to their
core and then match all forms of the word. For example, searching
for serach would properly locate search, but a search
for locks might find looks, whether or not that
- Phonetic, sound-alike or "Soundex" matching
uses linguistics to search for words which may sound similar.
This is particularly useful for names, so a search for licos
will find Lycos, but also brings up odd results: a search
for fuzzie may match fees or face.
5. Query Requirements Not Met
If the search engine automatically searches for all terms or a phrase,
or the query includes operators such as + or NOT, there may be no
pages which fulfill all the requirements. Examples include brown
bear(both terms), "Olympic gold medal" (phrase),
claymation +British (required term), MP3 NOT Napster
This can also happen when searching in a particular section or zone
of a site for words which are used in different sections of the site.
Yahoo and CNet are good examples where people can limit searches to
a subsection, but searching for roses in the tropical fish
area will never find a match.
What to do: Search engines which show the number of pages
matched for each term are particularly helpful in this case. The
no-matches page can clarify
which of the terms caused the problem and provide advice on how
to enlarge the search.