Search engine coverage bias: evidence and possible causes

Commercial search engines are now playing an increasingly important role in Web information dissemination and access. Of particular interest to business and national governments is whether the big engines have coverage biased towards the US or other countries. In our study we tested for national biases in three major search engines and found significant differences in their coverage of commercial Web sites. The US sites were much better covered than the others in the study: sites from China, Taiwan and Singapore. We then examined the possible technical causes of the differences and found that the language of a site does not affect its coverage by search engines. However, the visibility of a site, measured by the number of links to it, affects its chance to be covered by search engines. We conclude that the coverage bias does exist but this is due not to deliberate choices of the search engines but occurs as a natural result of cumulative advantage effects of US sites on the Web. Nevertheless, the bias remains a cause for international concern.     

Comparing rankings of search results on the Web

The Web has become an information source for professional data gathering. Because of the vast amounts of information on almost all topics, one cannot systematically go over the whole set of results, and therefore must rely on the ordering of the results by the search engine. It is well known that search engines on the Web have low overlap in terms of coverage. In this study we measure how similar are the rankings of search engines on the overlapping results.We compare rankings of results for identical queries retrieved from several search engines. The method is based only on the set of URLs that appear in the answer sets of the engines being compared. For comparing the similarity of rankings of two search engines, the Spearman correlation coefficient is computed. When comparing more than two sets Kendall’s W is used. These are well-known measures and the statistical significance of the results can be computed. The methods are demonstrated on a set of 15 queries that were submitted to four large Web search engines. The findings indicate that the large public search engines on the Web employ considerably different ranking algorithms.     

国外网络搜索引擎优秀资源现状述评——搜索引擎网站、论坛、新闻和学术会议资源

从优秀搜索引擎、搜索引擎网站、搜索引擎论坛、搜索引擎新闻和搜索引擎会议等方面入手,对国外现有论述搜索引擎的主要资源、种类、性能和特色进行了述评.在此基础上,推荐有关搜索引擎的最佳资源,为人们学习掌握搜索引擎的资源、搜索技巧、方法和优化检索策略提供参考资料和学习途径.     

Finding information on the World Wide Web: the retrieval effectiveness of search engines

Search engines are essential for finding information on the World Wide Web. We conducted a study to see how effective eight search engines are. Expert searchers sought information on the Web for users who had legitimate needs for information, and these users assessed the relevance of the information retrieved. We calculated traditional information retrieval measures of recall and precision at varying numbers of retrieved documents and used these as the bases for statistical comparisons of retrieval effectiveness among the eight search engines. We also calculated the likelihood that a document retrieved by one search engine was retrieved by other search engines as well.     

Managing web repositories in emerging economies: Case studies of browsing web directories

Over the past decade, worldwide Internet usage has grown tremendously, with the most rapid growth in some emerging economies such as Latin America and the Middle East, where people speaking different languages actively seek information on the web. Global search engines may not adequately address local users’ needs while regional web portals may lack rich web content. Different from search engines, web directories organize sites and pages into intuitive hierarchical structures to facilitate browsing. However, high-quality web directories in users’ native languages often do not exist and their development requires much domain knowledge not readily available. In this research, we proposed a novel semi-automatic approach to facilitate web repository management. We applied the approach to developing web directories in the business and health-care domains for the Spanish-speaking and Arabic-speaking communities respectively. The two directories contain respectively 4735 and 5107 unique sites and pages with a maximum depth of 5 levels. Results of experiments involving 37 native speakers show that these directories outperformed existing benchmark directories in terms of browsing effectiveness and efficiency, providing strong implications for information professionals and multinational enterprise managers.     

How are we searching the World Wide Web? A comparison of nine search engine transaction logs

The Web and especially major Web search engines are essential tools in the quest to locate online information for many people. This paper reports results from research that examines characteristics and changes in Web searching from nine studies of five Web search engines based in the US and Europe. We compare interactions occurring between users and Web search engines from the perspectives of session length, query length, query complexity, and content viewed among the Web search engines. The results of our research shows (1) users are viewing fewer result pages, (2) searchers on US-based Web search engines use more query operators than searchers on European-based search engines, (3) there are statistically significant differences in the use of Boolean operators and result pages viewed, and (4) one cannot necessary apply results from studies of one particular Web search engine to another Web search engine. The wide spread use of Web search engines, employment of simple queries, and decreased viewing of result pages may have resulted from algorithmic enhancements by Web search engine companies. We discuss the implications of the findings for the development of Web search engines and design of online content.     

Tagging and searching: Search retrieval effectiveness of folksonomies on the World Wide Web

Many Web sites have begun allowing users to submit items to a collection and tag them with keywords. The folksonomies built from these tags are an interesting topic that has seen little empirical research. This study compared the search information retrieval (IR) performance of folksonomies from social bookmarking Web sites against search engines and subject directories. Thirty-four participants created 103 queries for various information needs. Results from each IR system were collected and participants judged relevance. Folksonomy search results overlapped with those from the other systems, and documents found by both search engines and folksonomies were significantly more likely to be judged relevant than those returned by any single IR system type. The search engines in the study had the highest precision and recall, but the folksonomies fared surprisingly well. Del.icio.us was statistically indistinguishable from the directories in many cases. Overall the directories were more precise than the folksonomies but they had similar recall scores. Better query handling may enhance folksonomy IR performance further. The folksonomies studied were promising, and may be able to improve Web search performance.     

Web search engine multimedia functionality

Web search engines are beginning to offer access to multimedia searching, including audio, video and image searching. In this paper we report findings from a study examining the state of multimedia search functionality on major general and specialized Web search engines. We investigated 102 Web search engines to examine: (1) how many Web search engines offer multimedia searching, (2) the type of multimedia search functionality and methods offered, such as “query by example”, and (3) the supports for personalization or customization which are accessible as advanced search. Findings include: (1) few major Web search engines offer multimedia searching and (2) multimedia Web search functionality is generally limited. Our findings show that despite the increasing level of interest in multimedia Web search, those few Web search engines offering multimedia Web search, provide limited multimedia search functionality. Keywords are still the only means of multimedia retrieval, while other methods such as “query by example” are offered by less than 1% of Web search engines examined.     

中外文搜索引擎自然语言问答能力的比较与评价研究

【目的/意义】对Google、Bing、百度和搜狗四个中外文搜索引擎的自然语言问答能力进行评价,以揭示搜 索引擎正在向兼具搜索和自动问答功能的系统演进的趋势,对不同搜索引擎在不同类型问题上的自然语言回答能 力进行比较。【方法/过程】从文本检索会议和自然语言处理与中文计算会议的问答系统评测项目抽取了三类问题 （人物类、时间类、地点类）,并进行搜索,以搜索引擎是否返回准确答案或包含正确答案的精选摘要为标准进行人 工评分,使用单因素方差分析和多重比较检验的方法进行比较分析。【结果/结论】主流的中外文搜索引擎均已具备 一定的自然语言问答能力,但仍存在较大的提升空间。Google总体表现最好,但对于人物类问题的回答能力弱于 搜狗。中外文搜索引擎在时间类问题上的表现均好于人物类和地点类问题。     

第三代搜索引擎的研究现状及其发展趋向探析

目前第三代搜索引擎研究多基于“技术驱动型”理念,即从技术角度改进搜索引擎来更好地满足用户需求。同时,以Jwmguagua等为主的搜索引擎本着“服务驱动型”理念,提出了第三代搜索引擎直潜全能搜索技术系统,使搜索引擎具有了直潜全能搜索能力。基于以上两种主要的搜索引擎发展理念,第三代搜索引擎呈现出多元化、个性化的发展趋向。     

Multimedia search capabilities of Chinese language search engines

This paper reports results from a study exploring the multimedia search functionality of Chinese language search engines. Web searching in Chinese (Mandarin) is a growing research area and a technical challenge for popular commercial Web search engines. Few studies have been conducted on Chinese language search engines. We investigate two research questions: which Chinese language search engines provide multimedia searching, and what multimedia search functionalities are available in Chinese language Web search engines. Specifically, we examine each Web search engine’s (1) features permitting Chinese language multimedia searches, (2) extent of search personalization and user control of multimedia search variables, and (3) the relationships between Web search engines and their features in the Chinese context. Key findings show that Chinese language Web search engines offer limited multimedia search functionality, and general search engines provide a wider range of features than specialized multimedia search engines. Study results have implications for Chinese Web users, Website designers and Web search engine developers.     

Discriminating meta-search: a framework for evaluation

There was a proliferation of electronic information sources and search engines in the 1990s. Many of these information sources became available through the ubiquitous interface of the Web browser. Diverse information sources became accessible to information professionals and casual end users alike. Much of the information was also hyperlinked, so that information could be explored by browsing as well as searching. While vast amounts of information were now just a few keystrokes and mouseclicks away, as the choices multiplied, so did the complexity of choosing where and how to look for the electronic information. Much of the complexity in information exploration at the turn of the twenty-first century arose because there was no common cataloguing and control system across the various electronic information sources. In addition, the many search engines available differed widely in terms of their domain coverage, query methods and efficiency.Meta-search engines were developed to improve search performance by querying multiple search engines at once. In principle, meta-search engines could greatly simplify the search for electronic information by selecting a subset of first-level search engines and digital libraries to submit a query to based on the characteristics of the user, the query/topic, and the search strategy. This selection would be guided by diagnostic knowledge about which of the first-level search engines works best under what circumstances. Programmatic research is required to develop this diagnostic knowledge about first-level search engine performance.This paper introduces an evaluative framework for this type of research and illustrates its use in two experiments. The experimental results obtained are used to characterize some properties of leading search engines (as of 1998). Significant interactions were observed between search engine and two other factors (time of day and Web domain). These findings supplement those of earlier studies, providing preliminary information about the complex relationship between search engine functionality and performance in different contexts. While the specific results obtained represent a time-dependent snapshot of search engine performance in 1998, the evaluative framework proposed should be generally applicable in the future.     

Do your friends make you smarter?: An analysis of social strategies in online information seeking

Prior research in the social search space has focused on the informational benefits of collaborating with others during web and workplace information seeking. However, social interactions, especially during complex tasks, can have cognitive benefits as well. Our goal in this paper is to document the methods and outcomes of using social resources to help with exploratory search tasks. We used a talk-aloud protocol and video capture to explore the actions of eight subjects as they completed two “Google-hard” search tasks. Task questions were alternated between a Social and Non-Social Condition. The Social Condition restricted participants to use only social resources—search engines were not allowed. The Non-Social Condition permitted normal web-based information sources, but restricted the use of social tools.     

聚类在搜索引擎中的应用

本文介绍了目前较为流行的搜索引擎聚类技术,对国外著名聚类搜索引擎进行了测评,并预测了搜索引擎聚类技术的未来发展。     

四大搜索引擎网站声誉评价能力研究

本文在分析网站声誉及其评价指标的基础上,对Google、AltaVista、Lycos和Yahoo四大基于三种不同技术的搜索引擎的输出网站的声誉进行用户评价,结果表明Google的各项指标均优于其它三个搜索引擎,在网站声誉评价的能力方面,基于链接结构分析技术的搜索引擎强于基于内容分析技术和基于人工指定目录技术的搜索引擎。     

因特网上的图像搜索引擎

The operating principle of Web-based image search engines is briefly described. A detailed evaluation of some of image search engines is made. Finally, the paper points out the deficiencies of the present image search engines and their development trend.     

Search Engines as Substitutes for Traditional Information Sources? An Investigation of Media Choice

We develop a two-phased survey design—based on the uses and gratifications approach and the theory of planned behavior—to analyze competitive relations between search engines and traditional information sources. We apply the survey design in a large-scale empirical study with 14-to 66-year-old Internet users (mean age 32) to find out whether complementary or substitutional dependencies predominate between search engines and three traditional information sources—paper-based encyclopedias and yellow pages and telephone-based directory assistance. We find that search engines, compared to the traditional alternatives, are gratifying a wider spread of users' needs. Although yellow pages and directory assistance are potentially substitutable, encyclopedias serve those needs that search engines cannot (yet) fulfill. The traditional media companies face increased competition, but do not necessarily have to be in an inferior competitive position.     

Improving educational web search for question-like queries through subject classification

Students use general web search engines as their primary source of research while trying to find answers to school-related questions. Although search engines are highly relevant for the general population, they may return results that are out of educational context. Another rising trend; social community question answering websites are the second choice for students who try to get answers from other peers online. We attempt discovering possible improvements in educational search by leveraging both of these information sources. For this purpose, we first implement a classifier for educational questions. This classifier is built by an ensemble method that employs several regular learning algorithms and retrieval based approaches that utilize external resources. We also build a query expander to facilitate classification. We further improve the classification using search engine results and obtain 83.5% accuracy. Although our work is entirely based on the Turkish language, the features could easily be mapped to other languages as well. In order to find out whether search engine ranking can be improved in the education domain using the classification model, we collect and label a set of query results retrieved from a general web search engine. We propose five ad-hoc methods to improve search ranking based on the idea that the query-document category relation is an indicator of relevance. We evaluate these methods for overall performance, varying query length and based on factoid and non-factoid queries. We show that some of the methods significantly improve the rankings in the education domain.     

垂直和通用搜索引擎的差异和案例分析

垂直搜索被普遍认为将是下个潜力市场,是搜索引擎的细分和延伸。是对某类网页资源和结构化资源的深度整合。本文综合分析了垂直搜索的特性,并从信息采集、信息索引和信息处理方面分析其同通用搜索引擎的差异,然后通过垂直搜索在电子政务上的强势进入的案例来分析其应用发站的特性。     

Search Engines as Substitutes for Traditional Information Sources? An Investigation of Media Choice

We develop a two-phased survey design—based on the uses and gratifications approach and the theory of planned behavior—to analyze competitive relations between search engines and traditional information sources. We apply the survey design in a large-scale empirical study with 14-to 66-year-old Internet users (mean age 32) to find out whether complementary or substitutional dependencies predominate between search engines and three traditional information sources—paper-based encyclopedias and yellow pages and telephone-based directory assistance. We find that search engines, compared to the traditional alternatives, are gratifying a wider spread of users' needs. Although yellow pages and directory assistance are potentially substitutable, encyclopedias serve those needs that search engines cannot (yet) fulfill. The traditional media companies face increased competition, but do not necessarily have to be in an inferior competitive position.