Combining Information from Multiple Internet Sources

Consensus Ask.com Live Interia Yahoo! Google
Set Coverage 70% 50% 80% 70% 80%
URL to URL 20% 20% 10% 20% 10%
Table 4.1.6 Coverage of results of Consensus method and search engines for simple query
Table 4.1.5 presents the comparison of result sets between Consensus method and each of
the result sets returned by the search engines. Table 4.1.6 presents the sets coverage. Sets setcoverage
is at least 50% but URL to URL coverage is very low and is at most 20%. Also the result
set which was provided by Consensus method was not consistent. It means that average of distances
(Levenshtein) between consensus answer and the result set each of the search engines was higher
than average of distance between result sets between search engines. This shows that the result sets
are dispersed in the sense of the Levenshtein distance.
Consensus method’s answer processing algorithm is based on average ranks of the URLs
from the result sets of the engines - in the final answer there will be overall highest ranked URLs. If
an URL was at the top places throughout the result sets of the engines, it will be at one of the
topmost places in the consensus answer. If its overall ranking was low it will be on low place or not
at all in the final answer.
When measuring distances between result set using Levenshtein distance, this method is
highly dependent on URL positions – where a particular URL is placed in first set and where it is
placed in the second set, highly contributes to the final distance value. It can be observed that URL
coverage of the consensus answer is very low for each result set. This resulted in a consensus
answer which is said to be inconsistent. Nevertheless, it is a subjective result, the inconsistency. If
to use some other metric of measuring distance, it could happen that the result would be marked as
being consistent.
48