The increase in the number of shared devices can in part be understood by analyzing the population of “reactivated” devices. Reactivated devices are devices that iovation re-identifies after having not seen the device for more than 90 days. By studying these devices in contrast to the device population as a whole, it is clear that iovation’s expanding customer base is a significant contributor to this trend as a vast majority of reactivated devices have been seen in multiple customer networks.

Since the beginning of 2008, iovation’s reactivated device rate has doubled every 5 months and continues to climb. This demonstrates that as iovation’s device network continues to grow, device crossover is also increasing.

Inactive Devices

As iovation’s device network grows and evolves, it is useful to distinguish between active and inactive devices since active devices have more interesting behavior and are involved in fraudulent or abusive activity now. To answer the question “what is active?”, I measured the percentage of devices that are re-identified over varying periods of time. Graphing the result of this analysis produces a curve that tails off considerably by 90 days, which means a very small percentage of devices that have not been identified in the preceding 90 days will ever be identified again. Therefore, for this study, devices that had not been re-identified in the last 90 days were considered to be inactive. This data set is based on data from the first 3 months of 2008.

How to read this graph: Devices not seen for 30 days have an approximately 40% chance of returning, whereas devices not seen for 90 days have an approximately 1% chance of returning.

Reactivated Devices

Devices that are re-identified after more than 90 days of inactivity are considered reactivated devices.

For the 18-month period from April 2008–September 2009, the following chart shows the percentage of the active device population that is made up of reactivated devices.

For the month of September 2009, I compared the population of active devices with the population of reactivated devices to see how their characteristics differ. From that comparison, it was determined that:

• Reactivated devices are 3 times more likely than all active devices to have been seen in more than one customer network.
• Reactivated devices are no more or less likely to have a reputation.

The following chart shows the percentage of reactivated devices that had subscriber cross-over as compared to the percentage of all active devices with subscriber cross-over.

Conclusion

Analysis of iovation’s network shows a clear correlation between reactivated devices and devices with cross-over between subscribers, and we are seeing a significant increase in both as the number of our subscribers grows. This upholds our belief that a database of device reputations, shared by online companies, across multiple industries, offers valuable and relevant information to individual sites in their fight against online fraud and abuse.