PREDICTING PERFORMANCE OF CONTENT ITEMS PRESENTED TO USERS OF AN ONLINE SYSTEM BASED ON CONTEXTS IN WHICH THE CONTENT ITEMS ARE PRESENTED TO THE USERS

1 . A method comprising:

obtaining one or more content items at an online system for presentation to users of the online system;

maintaining information at the online system describing contexts in which content items are presented to users of the online system, a context in which a content item is presented to a user identifying one or more of: content presented in conjunction with the content item, content presented prior to presentation of the content item, an action performed by a user prior to presentation of the content item, and any combination thereof;

determining a quality score for each of at least a set of contexts in which content items are presented to users of the online system, the quality score for a context based on actions performed by users of the online system who were previously presented with one or more content items in the context;

identifying a context in which a selected content item is to be presented to users of the online system;

retrieving a quality score for the identified context; and

determining a predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item.

2 . The method of claim 1 , wherein determining the predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item comprises:

determining the predicted performance of the selected content item as a product of a percentage of presentations of the selected content item in a particular location and a constant raised to a power of the quality score of the identified context.

3 . The method of claim 2 , wherein the constant is two.

4 . The method of claim 1 , wherein the selected content item includes a bid amount

5 . The method of claim 4 , wherein determining the predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item comprises:

determining the predicted performance of the selected content item as a product of a percentage of presentations of the selected content item in a particular location and a constant raised to a power of the quality score of the identified context, and a conversion factor based on the bid amount included in the selected content item and likelihoods of users in the location viewing the selected content item or performing interactions after being presented with the selected content item.

6 . The method of claim 5 , wherein determining the predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item comprises:

determining the predicted performance of the selected content item as a product of the percentage of presentations of the selected content item in a particular location, the constant raised to the power of the quality score of the identified context, and a conversion factor based on the bid amount included in the selected content item and likelihoods of users in the location viewing the selected content item or performing interactions after being presented with the selected content item, and a ratio of a number of presentations of the content item during an interval to a presentation constant.

7 . The method of claim 1 , further comprising:

presenting the selected content item to users of the online system;

determining performance of the selected content item from information received after presentation of the selected content item to users of the online system;

comparing the predicted performance of the content item to the determined performance of the selected content item; and

identifying an alternate context in which the selected content item is to be presented in response to the comparison indicating greater than a threshold difference between the predicted performance of the content item and the selected content item.

8 . The method of claim 7 , further comprising:

determining a predicted performance of the selected content item based on a quality score for the alternate context.

9 . The method of claim 1 , wherein the context in which the content item is presented to the user identifies one or more selected from a group consisting of: if the content item is to be presented after a user performs an action, if the content item is to be presented prior to a user performing the action, if the content item is to be presented when a user performs the action, other content presented when the content item is also presented, if the content item is presented in a particular format, and any combination thereof.

10 . The method of claim 1 , wherein maintaining information at the online system describing contexts in which content items are presented to users of the online system comprises:

maintaining identifiers of applications that present content items provided by the online system;

maintaining a set of contexts associated with each identifier, the set of contexts associated with an identifier specifying contexts in which an application corresponding to the identifier presented one or more content items.

11 . The method of claim 1 , wherein identifying the context in which the selected content item is to be presented to users of the online system comprises:

identifying the context as a context identified by information received by an application identifying a context in which the application presented the selected content item.

12 . The method of claim 1 , wherein identifying the context in which the selected content item is to be presented to users of the online system comprises:

applying one or more models to characteristics of the selected content item to determine likelihoods of the selected content item being presented in different contexts; and

identifying the context in which the selected content item is to be presented to users of the online system based on the determined likelihoods.

13 . A computer program product comprising a computer-readable storage medium having instructions encoded thereon that, when executed by a processor, cause the processor to:

obtain one or more content items at an online system for presentation to users of the online system;

maintain information at the online system describing contexts in which content items are presented to users of the online system, a context in which a content item is presented to a user identifying one or more of: content presented in conjunction with the content item, content presented prior to presentation of the content item, an action performed by a user prior to presentation of the content item, and any combination thereof;

determine a quality score for each of at least a set of contexts in which content items are presented to users of the online system, the quality score for a context based on actions performed by users of the online system who were previously presented with one or more content items in the context;

identify a context in which a selected content item is to be presented to users of the online system;

retrieve a quality score for the identified context; and

determine a predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item.

14 . The computer program product of claim 13 , wherein determine the predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item comprises:

determine the predicted performance of the selected content item as a product of a percentage of presentations of the selected content item in a particular location and a constant raised to a power of the quality score of the identified context.

15 . The computer program product of claim 13 , wherein the selected content item includes a bid amount

16 . The computer program product of claim 15 , wherein determine the predicted performance of the content item based the retrieved quality score for the identified context and one or more characteristics of the selected content item comprises:

determine the predicted performance of the selected content item as a product of a percentage of presentations of the selected content item in a particular location, a constant raised to a power of the quality score of the identified context, and a conversion factor based on the bid amount included in the selected content item and likelihoods of users in the location viewing the selected content item or performing interactions after being presented with the selected content item, and a ratio of a number of presentations of the content item during an interval to a presentation constant.

17 . The computer program product of claim 13 , wherein the computer readable storage medium further has instructions encoded thereon that, when executed by the processor, cause the processor to:

present the selected content item to users of the online system;

determine performance of the selected content item from information received after presentation of the selected content item to users of the online system;

compare the predicted performance of the content item to the determined performance of the selected content item; and

identify an alternate context in which the selected content item is to be presented in response to the comparison indicating greater than a threshold difference between the predicted performance of the content item and the selected content item.

18 . The computer program product of claim 17 , wherein the computer readable storage medium further has instructions encoded thereon that, when executed by the processor, cause the processor to:

determine a predicted performance of the selected content item based on a quality score for the alternate context.

19 . The computer program product of claim 13 , wherein the context in which the content item is presented to the user identifies one or more selected from a group consisting of: if the content item is to be presented after a user performs an action, if the content item is to be presented prior to a user performing the action, if the content item is to be presented when a user performs the action, other content presented when the content item is also presented, if the content item is presented in a particular format, and any combination thereof.

20 . The computer program product of claim 17 , wherein identify the context in which the selected content item is to be presented to users of the online system comprises:

identify the context as a context identified by information received by an application identifying a context in which the application presented the selected content item.