1. A method comprising: transmitting, from an online system to a client device, third-party content originating from a third-party system, the third-party content for presentation in a client application associated with the online system and including a pointer to a third-party application associated with the third-party system; obtaining an attribution identifier and an interaction with the third-party content by a user of the client device via the client application, the attribution identifier generated in response to the interaction, and the interaction causing the client device to execute the third-party application using the pointer; receiving, from the third-party system, an attribution identifier and information describing interaction by the user with the third-party application; determining, by a processor, whether the attribution identifier obtained from the client device matches the attribution identifier received from the third-party system; and associating the information describing interaction by the user with the third-party application with the interaction with the third-party content by the user of the client device via the client application responsive to determining that the attribution identifier obtained from the client devices matches the attribution identifier received from the third-party system.