Tie breaking rules for content item matching

A non-transitory computer readable medium storing instructions that upon execution by one or more data processing apparatus cause the one or more data processing apparatus to perform operations comprising:

• receiving a content item request that specifies a phrase of one or more words;
• determining that a first keyword and a second keyword for a same content distribution campaign are both matched by the phrase;
• determining that a first match between the first keyword and the phrase is a more specific match than a second match between the second keyword and the phrase;
• determining that the first keyword is associated with a higher bid than the second keyword;
• identifying, based on the determination that the first keyword is associated with the higher bid, a first tiebreaker rule specifying that the second keyword is a controlling keyword when the second keyword has a higher quality score than the first keyword;
• determining which of the first keyword or the second keyword has a higher quality score;
• selecting, based on the first tiebreaker rule and the determination of which of the first keyword or the second keyword has a higher quality score, one of the first keyword or the second keyword as a controlling keyword for the content item request;
• and
• providing, in response to the content item request, data associated with the controlling keyword.

A system comprising:

• a data store storing keywords for one or more content distribution campaigns and bids that are associated with the keywords;
• and
• one or more data processing apparatus that interact with the data store and execute instructions that cause the one or more data processing apparatus to perform operations comprising:
• receiving a content item request that specifies a phrase of one or more words;
• determining, based on the stored keywords, that a first keyword and a second keyword for a same content distribution campaign are both matched by the phrase;
• determining that a first match between the first keyword and the phrase is a more specific match than a second match between the second keyword and the phrase;
• determining, based on the stored bids, that the first keyword is associated with a higher bid than the second keyword;
• identifying, based on the determination that the first keyword is associated with the higher bid, a first tiebreaker rule specifying that the second keyword is a controlling keyword when the second keyword has a higher quality score than the first keyword;
• determining which of the first keyword or the second keyword has a higher quality score;
• selecting, based on the first tiebreaker rule and the determination of which of the first keyword or the second keyword has a higher quality score, one of the first keyword or the second keyword as a controlling keyword for the content item request;
• and
• providing, in response to the content item request, data associated with the controlling keyword.