Simulating content item selection events in a computer system

A method comprising:

• identifying a first plurality of content item selection events in which a content item of a first content provider was a candidate for selection;
• for each content item selection event of the first plurality of content item selection events:
• determining a first amount that the first content provider contributed to said each content item selection event;
• simulating said each content item selection event by removing the content item of the first content provider from consideration, wherein simulating comprises determining a second amount that a different content provider different than the first content provider would have contributed to said each content item selection event if the different content provider was selected for said each content item selection event instead of the first content provider;
• determining a first total of the first amounts determined for the first plurality of content item selection events;
• determining a second total of the second amounts determined for the first plurality of content item selection events;
• based on the first total and the second total, calculating a first incremental value for the first content provider;
• calculating a first ratio of the first incremental value to the first total;
• based on the first ratio, causing data about the first content provider to be displayed on a screen of a computing device.

A system comprising:

• one or more processors;
• one or more storage media storing instructions which, when executed by the one or more processors, cause:
• identifying a plurality of content item selection events in which a content item of a first content provider was a candidate for selection;
• for a first content item selection event of the plurality of content item selection events, determining a first amount that the first content provider contributed as a result of being selected for the first content item selection event;
• simulating the first content item selection event by determining a second amount that a second content provider would have contributed as a result of the first content item selection event if the second content provider was selected for the first content item selection event instead of the first content provider;
• simulating a second content item selection event of the plurality of content item selection events by determining a difference between (1) a third amount that a third content provider contributed as a result of being selected for the second content item selection event and (2) a fourth amount that the third content provider would have contributed if the first content provider was not a candidate for selection in the second content item selection event;
• based on the first amount, the second amount, and the third amount, calculating an incremental value ratio for the first content provider;
• based on the incremental value ratio, causing data about the first content item provider to be displayed on a screen of a computing device.