Constructing a Search Strategy #2 - Boolean Operators

Computers are basically giant calculators. Databases and search engines can't think of words the same way we do - as signs representing meanings. They have to think of a word as a thing that can be used in sums.

An illustration I like using is to think about a deck of cards. You can tell the computer to find all of the black cards and it will. You can tell it to find all of the hearts, and it will. You can tell it to find all of the Jacks, and it will - but you can't tell it to find a royal flush, because then it has to think about how the cards relate to each other. Unless you tell the computer exactly what cards are in a royal flush, then it won't be able to find one for you.

This is where Boolean Operators come in. They act as commands telling the computer how the words relate to each other and what should be done about them.

The most common Boolean terms are AND, OR and NOT.

AND tells the database to look specifically for documents that have both of the terms you are searching for. For example, if you ran a search for "rotator cuff", you might get several hundred results. If you ran a search for "injury", you might get several thousand. Most of those articles would be completely useless for an assignment about rotator cuff injuries. However, if you searched for "rotator cuff" AND "injury", the database would only return search results with both terms. It would not find any articles about rotator cuffs that did not include the word "injury", nor would it return any articles about injuries that did not mention "rotator cuff". This could cut the results down from thousands to only a hundred or so. Any other terms you added with an AND would cut the number of results even further.

But what if there was a brilliant journal article that consistently used the word "shoulder" instead of "rotator cuff"? The search above wouldn't find it, because it was missing one of the essential search terms.

This is where OR comes in.

You use OR to tell the database or search engine that these words are interchangeable, and you and happy to accept any article with either (or both). So, ("rotator cuff" OR "shoulder") AND "injury" should pick up any articles that use "shoulder" instead of "rotator cuff", and make sure the word "injury" is included. The brackets in this case are just like the brackets in a mathematical problem - they help the computer to know which 'sums' to do first in the 'equation'.

OR can also help with controlling your search. Say you particularly wanted to know about rotator cuff injuries in sports that involve over-arm bowling. The most obvious ones are cricket and baseball, so you could run a search that looked like this: ("rotator cuff" OR "shoulder") AND ("cricket" OR "baseball") AND "injury".

You will probably find the thousands of results you had to start with have now been whittled down to twenty or so.

Now, if you found you were constantly getting articles about lacrosse, and you wanted to get rid of them from your search results, you would think about using NOT.

NOT basically tells the database or search engine to shut out any articles containing those terms. So, adding NOT "lacrosse" to your search would get rid of any articles containing the word "lacrosse".

Of course, there might be a really good article that uses the word "lacrosse" in one sentence, and the database will reject it just like all of the other lacrosse related articles. You should think carefully about using NOT in your searches. It can be very useful for getting rid of 'noise', but it can have it's downside.

There are other Boolean Operators that you can use in different databases and search engines, but these three are standard for almost all of them. You should check the database guides for the particular database you want to use to see what other operators it offers you.

Why use journals?

Once upon a time students asked me why they should use journals when all of the information should be in a book some where. These days they ask me why they should use journals when all of the information should be on a website some where.

Well, there are a number of very good reasons why journals should be at the top of your "must see" list whenever you do any research. Here are some of them:

Journals have the latest research. Information will appear in journals years before it turns up in a book - and if new studies reveal that the old information is incorrect, those studies will be published in journals fairly quickly, while the books will take a lot longer to correct.

Some articles will only appear in journals. Not everything that is published in a journal will make it to a different form of publication (no, not even on the web). A lot of the best research will only ever appear in journals.

Journals can be more trustworthy than other sources. Peer reviewed journals have been checked and vetted by a number of other experts in the fields. Books don't always have the same checks and balances (it depends on the publisher), and web pages can be downright dangerous (although some are trustworthy). Information in a peer reviewed journal is usually a safe bet.

Journals are indexed. Most journals - especially peer reviewed journals - are indexed in databases. Someone has gone through and taken not of every aspect of the journal articles - their titles, authors, subject areas, keywords... And all of this information is searchable through the databases. This means they are actually one of the easier forms of information to look for, if you know how to use the databases to find them. Very few books are indexed, so it's much harder to find a book that has the information you want. Technically, almost all web pages are indexed, but not generally in databases. To find them you have to use a search engine, and search engines are not as powerful or useful as databases.

A lot of journals are online. If your library subscribes to the electronic version of the journal, you may find that you can download most of the articles you want from the comfort of your own computer. Now, the older the journal issues are, the more likely it is that you'll have to find them in print, but most of the journals published in the last ten years have electronic versions.

Journals are almost always available. Most academic libraries (and some others) treat their journals like reference books - they are not available for loan, so they are always available for use. Even if every decent book on the subject was borrowed out weeks ago, you can usually find enough journal articles to produce a quality assignment. Plus, electronic subscriptions very rarely go "missing from the shelves", so even if the library burns down you would still be able to do your research.

All in all, journals are the best resources to use when researching. They are the kings of the information world, and you should get into the habit of using them as soon as possible. Your grades will thank you for it.

A couple of Search Engines

While it may seem as if the entire world is covered by Google, and therefore one need not look elsewhere, Google is not the be-all and end-all of search engines, and anyone serious about finding good information on the Web should have at least two decent search engines in their bag of tricks.

Why do you need more than one search engine? Because of maths.

You see, no matter how smart and pretty computers may appear, they can still really only do one thing well: count. They're still giant calculators at heart. In order to "think" about web pages, they have to give every factor involved (the words in your search, how often they turn up on a page, where they turn up on the page) a numerical value. They then use a mathematical formula, or algorithm, to rank the pages in a list. Different search engines use different algorithms, which means you get different results.

Google and Yahoo! are both general search engines. Their algorithms are designed to find the most "popular" websites by canvassing all of the sites they know about, picking the ones with the most links pointing to them and ranking them according to factors like commercial relevance. They are the K-marts and Targets of search engines. By all means, use them - you'll probably find something that's just what you're looking for, but remember to shop around in the specialty stores as well.

A personal favourite of mine has always been Ask. Well, technically, it hasn't 'always' been Ask. It used to be about three different search engines, Hotbot, Teoma and Ask Jeeves, which were all available separately and via the Hotbot home page. Hotbot sold out to Google then curled up and died, while Teoma and Ask Jeeves merged into Ask.

Ask combines the best features of both search engines, using the Teoma algorithm and Ask Jeeve's ability to recognise questions. Where Google's algorithm goes for the most popular web sites across the board, Ask attaches a few more numbers to the web sites in it's database and looks for the sites which are most popular amongst their peers.

In addition, Ask also offers three sets of results. There's the normal "hit list" of links to web pages, and two areas where they offer search suggestions based on tallied results of other, similar questions: "Narrow Your Search" and "Expand Your Search". Depending on what you search for, you'll also see examples from the Images search in another part of the screen.

Another search engine I have discovered very recently is Vivisimo (which also seems to be Clusty - I'm not entirely sure what the exact relationship is between these two). Vivisimo/Clusty subdivides it's results and groups (clusters) them together based on common content, which makes it much easier to sort through the results and hone in on those which seem most relevant. I spent several hours looking for information through several other search engines which I managed to find in minutes using Vivisimo, so it's definitely worth adding to the toolbox.

Have a play with them and get a feel for the ways they complement each other. Try putting the same search terms (or question) into each, and see what comes up. And remember to look beyond the first ten results - you can often find just what you're looking for on page 5.