BACKGROUND

This specification relates to processing local search results.

The Internet provides access to a wide variety of resources such as video or audio files, web pages for particular subjects, book articles, or news articles. A search system can identify resources in response to a search query that includes one or more search phrases (i.e., one or more words). The search system ranks the resources based on their relevance to the search query and on measures of quality of the resources and provides search results that link to the identified resources. The search results are typically ordered for viewing according to the rank.

Some search systems can obtain or infer a location of a user device from which a search query was received and include local search results that are responsive to the search query. A local search result is a search result that references a local document. A local document, in turn, is a document that has been classified as having local significance to particular locations of user devices. Accordingly, a local document may receive a search score “boost” for a query if the location associated with the local document is near the location of the user device. For example, in response to a search query for “coffee shop,” the search system may provide local search results that reference web pages for coffee shops near the location of the user device. Many users in various geographic regions will likely be satisfied with receiving local results for coffee shops in response to the search query “coffee shop” because it is likely that a user submitting the query “coffee shop” is interested in search results for coffee shops that are local to the user's location.

Some local results, however, may have very high scores independent of the local scoring boost. This score, which is referred to as a “location independent score,” may be high due to the document being of interest to people outside of a region that includes the location of the local result. For example, a restaurant may have a very unique name, and may also be a famous restaurant nationwide. Accordingly, although the restaurant has local significant, it may still be of very great interest to users nationwide. Thus, a search algorithm that takes into account search traffic and query log data may rank a document for the restaurant (e.g., a web page) very high.

By way of another example, a power company named after Thomas Edison may have very heavy local traffic in a large state. Thus, the search algorithm that takes into account search traffic and query log data will also rank a document for the power company very high due to the sheer volume or traffic to the webpage by its many customers. However, the power company webpage may be of very little interest to a user several states away. For example, a user may desire to learn about Thomas Edison, and not the power company that bears his name. However, due to the large volume of traffic to the power company web page, that web page may be ranked higher than a webpage about the man, the latter of which is more likely to be of interest to a user that inputs the query “Edison.”

SUMMARY

In general, one innovative aspect of the subject matter described in this specification can be embodied in methods that include the actions of receiving data specifying a search query, and a location of a user device from which the search query was received; receiving data specifying a set of documents determined to be relevant to the search query, the data specifying, for each of the documents, a respective search score indicative of the relevance of the document to the query and a ranking of the documents according to a first order based on the search scores, and wherein a proper subset of the documents are local documents, wherein each of the local documents is a document that is specified as having local significance to a geographic location of a user device; determining that a first local document in the proper subset of the local documents is eligible for a demotion operation that adjusts its respective search score to demote the rank of the first local document in the first order, the determination based at least in part on a proximity measure based on the geographic location of the user device and a geographic location specified for the first local document, and in response to the determination: for each second local document in the proper subset of local documents, determining a proximity measure that is based on the geographic location of the user device and the geographic location specified for the second local document; and adjusting the search score of the first local document to demote its ranking the first order when at least one of the proximity measures indicates a respective second local document has a specified geographic location that is within a threshold distance of the geographic location of the user device. Other embodiments of this aspect include corresponding systems, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.

These and other embodiments can each optionally include one or more of the following features. The method can further include, in response to determining that a first local document in the proper subset of the local documents is eligible for a demotion operation, determining that at least one document in the set of documents that is not a local document has a search score that meets a distant document demotion threshold and in response adjusting the search score of the first local document to demote its ranking in the first order so that the rank of the first local document relative to the rank of the at least one document is decreased.

Adjusting the search score of the first local document to demote its ranking in the first order so that the rank of the first local document relative to the rank of the at least one document is decreased can include adjusting the search score of the first local document to demote its ranking in the first order so that the rank of the at least one document is greater than the rank of the first local document.

The determination based at least in part on the proximity measure based on the geographic location of the user device and a geographic location specified for the first local document can include determining that the proximity measure indicates a distance between the geographic location of the user device and a geographic location specified for the first local document exceeds a maximum distance.

The determination is based at least in part on the proximity measure based on the geographic location of the user device and a geographic location specified for the first local document can include determining that the proximity measure indicates the geographic location of the user device and the geographic location specified for the first local document are not within a same region defined by a political boundary.

The search query can be a search query that does not include a location phrase that explicitly specifies a geographic location, and the data specifying a search query can include a local intent measure that is a measure of local intent for the search query.

The determining that a first local document in the proper subset of the local documents is eligible for a demotion operation can further include determining that the first local document is eligible for demotion based, in part, on local intent measure meeting a threshold value.

The data specifying a search query can include a local intent measure that is a measure of local intent for the search query, and adjusting the search score of the first local document to demote its ranking in the first order so that the rank of the first local document relative to the rank of the at least one document is decreased can include adjusting the search score of the first local document in inverse proportion to the local intent measure of the search query.

Determining that a first local document in the proper subset of the local documents is eligible for a demotion operation can further include determining that the first local document is eligible for demotion only if the first local document has a location independent search score component that does not meet distant document preservation threshold.

Particular embodiments of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages. A data processing apparatus can provide more relevant search results in response to receipt of a single general search query with an implicit local intent by demoting local search results when the general search query is determined to be a locally significant search query for a particular user location, and the distance of the particular user location from the location associated with the local search result meets a distance requirement. However, local results for distant locations are not demoted if the local result has relatively high location independent search score, and thus otherwise information rich documents are not inadvertently demoted. Additionally, a local result for a distant location may not be demoted if there are no nearby local results, or if there are no other results having a relatively high location independent search score. Thus, a local document for a distant location will not be demoted if the remaining documents appear to be of less relevance.

The details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

