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Feb. 15, 2001

Picks of the Month

In Search of the Perfect Search Engine

Looking for the ultimate online guide to a topic you and your students are about to explore? Do you wonder if all the search tools are really just the same-and whether you'll ever find one that gives you fewer than 85,322 matches? Read on.

By: Judy Salpeter

They're called search sites or portals, they're available in growing numbers, and they all attempt to do the same basic thing: make it easy for you to find just the right information on the vast World Wide Web. Our mission: to evaluate several of the best known search portals from an educator's eye. How useful is each one at conducting the sorts of searches a student or teacher might need?

Our focus in testing search portals was on the search engines that are central to each of them: specifically, how flexibly they allow a searcher to specify the exact topic to be located and how effectively they find and display the best matches. In addition, all of these sites use some sort of directory that groups a large number of pre-reviewed sites into a variety of categories and subcategories. There are occasions-especially with directory-oriented portals such as Yahoo!-when clicking on links in the directory can bring you to a helpful resource almost as quickly as entering your request into the search window. For many of the other portals, the directory serves more as a supplement to the search process, making it possible to narrow in better after an initial search has been conducted.

We know that filtering mandates in many schools and states preclude the use of general-purpose search portals with younger students. If these constraints apply to you, we're hoping that the reviews here will be helpful for locating tools for your own professional use-and for providing guidance to parents interested in the best search engines for their kids at home. We will return to review several filtered search tools and directories next month, most of them geared to students under age 12.

Here's a look at the criteria we considered in comparing the search tools. To discover how they measured up to each of them, see the chart on pages 18-19.

Searching Techniques

COMPARE the search capabilities.

Basic Search

All sites reviewed here have a main search page with a box that allows you to enter a word, phrase, or series of search terms. All understand some "Boolean" terms (see "Boolean Terms at a Glance"). However, they differ in the exact way they expect the terms to be written-whether to use "AND" or "+" to require a term, for example-and how easy they make it for users to combine Boolean commands in complex ways. In addition, each search engine has a default mode that tells it what to do if you type in a series of words without any Boolean connectors. Those that default to an "AND" search generally make it easiest to narrow in quickly; you just add a word at a time to the search string until the results are as precise as you want. To speed up the search process and avoid irrelevant matches, most search engines disregard common "stop words"-words like the or when-that have been included in the search screen.

Advanced Search

All the reviewed sites, except Ask Jeeves, offer an advanced search screen of some sort-usually with an extensive menu of choices. Some advanced screens offer an alternate way of entering Boolean terms (checking a box that says "must contain these words," for example, sets up an "AND" search). In addition, many offer such options as limiting the types of sites to search (e.g., only sites in English or only ones with a .com suffix) or searching for matches only in the titles or URLs of Web pages.

How Results are Displayed

COMPARE the results display.

Order/Ranking of Results

Almost invariably, searches on interesting educational topics-even with the use of good search criteria-lead to hundreds or thousands of matches. If the first 20-30 matches are good ones, this shouldn't cause a problem. But how do the search engines decide which matches to display first? Each site uses its own formula for determining, and then sorting by, relevance. Factors involved in assessing relevance usually include:

• how many times the search terms were found in the site,
• where in the site they appear (if the terms are in the title or first paragraph, the site is generally a better match),
• in the case of an "OR" search, what percentage of search words are found at the site.

Some search sites also factor in criteria such as the popularity of a site (how often it was visited by previous searchers or how highly it was rated by volunteer or paid editors). Other search engines offer two sets of matches: those approved by their own directory editors and others from the Web at large.

Other Aspects of the Search Results Display

In addition to the formula used for matching and ranking sites, another factor that determines the value of a search engine is what information is displayed about each match. Generally the search tools list approximately ten matches per page, with the title of each matching site, its URL, and a brief synopsis. Sometimes this synopsis is in the form of a description based on reviews by directory editors or on the meta tags provided by the site's creators. In other cases, the engine simply displays the first several lines of the site. This is necessary when there are no meta tags or other summaries available, but some engines seem to default to this approach for all search results-an unfortunate choice, since menu items tend to be mixed in with headlines and other text in a rather haphazard, hard-to-read way.

A third approach-and one that turned out to be very useful when the matching text did not occur in the first few paragraphs of a site-is the one taken by Google, at its own site and at Yahoo!. Results display the actual phrases in which the desired matches first occur, making it easy for the searcher to see at a glance whether the match is an appropriate one. The use of bold text to highlight the matching words is another helpful feature offered by Google and several of the other engines.

Another important question to ask about each search tool is how it handles multiple matches from a single Web site. Grouping the matches so that an information-rich site is only listed once-along with some indication that other pages at the same site have valuable information-allows a search tool to pack many more relevant sites onto a single results page. Other helpful information provided by a few of the tools includes the relevancy ranking the search engine gave the site and the date the information was posted. (Warning: this date can be misleading, since old pages sometimes appear to be recent if the surrounding pages at the site were updated recently.)

Evaluating the Search

We tested the search engines using a variety of research questions. We began with a search for a fairly broad topic-information about Saturn's rings-by entering the search commands that would direct each engine to look for "Saturn and rings but not cars." Next we addressed another popular topic-the gods of ancient Egypt-and challenged the search engines to tackle the question of how the ancient Egyptians prayed. This turned out to be an interesting test, since some of the engines had a hard time combining the search phrase "ancient Egypt" with both "gods" and "pray," jumping instead to a variety of religious sites that had nothing to do with ancient Egypt.

We also looked for some comparatively obscure information-searching for an elementary school where the reviewer used to teach and for information on Josephine Tey's theory about King Richard III as discussed in her book, The Daughter of Time. Finally, we attempted to locate photos of baby giraffes using the search terms "baby" and "giraffe," either in conjunction with a multimedia menu choice or with the word "photo." In the chart, we summarize the results, focusing less on the number of matches than on the quality of those matches.

Other Features

COMPARE the extra features.

Although our primary focus here is on search capabilities, see our Web site for summaries of some extras offered by each site, including such things as headline news, proprietary databases, and language translators. We also took a quick look at the filtering options offered by these grown-up sites (with more to come next month when we return to kid-oriented search sites) and summarized the commercial aspects of each one.

No one search engine is likely to meet all your needs, and fortunately there's no need to choose just one. Here's hoping that our observations about the strengths and weaknesses of each of the tools reviewed might help you choose a few favorite start points for fruitful searches.

COMPARE the overall strengths and weaknesses.

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