In 2014, I presented at ACM MobileHCI the results of an in-situ study, where we observed in detail, what types of notifications 15 mobile phone users receive and how they handle them. One of the key findings, that keeps being cited in other works, is that people receive an average of 63.5 notifications per day. However, since this statistics was derived from a sample size of 15 people, I never felt too confident about it. I always wanted to validate these statistics on a much larger sample.
The opportunity came in the form of a data set, that we collected as part of a study to explore moments to engage with mobile phone users. Together with my intern Amalia Vradi and my colleague Souneil Park, we analyzed 794,525 notifications from 278 mobile phone users and how they were handled.
Our participants received a median number of 56 notifications per day, which does not indicate that the number of notifications has increased over the past years.
We identified 5 different groups of notifications and explored them separately:
- messaging (e.g. WhatsApp individual messages)
- group messaging (e.g. WhatsApp group messages)
- social networks (e.g. Facebook likes)
- non-social networks (e.g. Dropbox)
Comparing these groups, we found that messaging apps create most of the notifications and are the only app type where with a conversion rate of about 65%, notifications are reasonably effective.
Notifications from other types of notifications are not really effective rarely lead to a conversion (rates between ca. 15 and 25%). A surprisingly large fraction of notifications is received while the phone is unlocked or the corresponding app is in foreground, hinting at possibility to optimize for this scenario. Finally, we show that the main difference in handling notifications is how long users leave them unattended if they will ultimately not consume them.