A server computer system receives event logs from one or more client devices for multiple consumption sessions of an online media item. The event logs are received based on random schedules. The system determines, for various times, a first number of consumption sessions during which an event log is scheduled to be sent at the corresponding times. The system determines, for the various times, a second number of consumption sessions during which an event log was sent to the server computer system at the corresponding times. The determinations being based on the event logs. The system determine, for each of the times, a probability that consumption time for the online media item is the corresponding time or less. The determination is based on the first number and the second number. The system determines consumption time metrics for the online media item based the probabilities for the plurality of times.