OpenSignal: Adding a square inch to phone screen leads to 75 MB of extra data per month

People who use Android devices with larger screen sizes tend to consume more data, especially when using a Wi-Fi connection, according to a report from network research firm OpenSignal.

There has been a general assumption in the industry that consumers who use devices with larger screens consume more data, especially multimedia content such as video. However, OpenSignal quantified the relationship and found that there is a strong correlation between screen size and data usage over Wi-Fi, and a weaker correlation between screen size and data usage over cellular connections.

According to the firm's report, each additional square inch of screen area leads to 75 MB of extra data downloaded per month over a cellular connection, and each additional square inch of screen area leads to 288 MB of extra data downloaded per month over Wi-Fi. OpenSignal concluded that that, according to the data, most people are using their phones in the same way when they are on the go regardless of screen size.

For example, OpenSignal found that data use over Wi-Fi doubles from a device with a 6-square-inch screen (like a Samsung Galaxy Ace) to a device with a 9-square-inch screen (like a Samsung Galaxy S III).

OpenSignal noted that it obtained its findings from users of its Android app, which is why all the devices studied were running Android. A total of 9,962 distinct devices were used in compiling the report.

"While this may seem like a limitation, the vast fragmentation of Android devices gave us a very broad scope for examining the impact of screen size on user behaviour," the firm noted. "In order to be included the individual device-user had to have accessed both cellular and Wi-Fi data on the same day. For similar reasons we restricted our data to areas with a high level of Wi-Fi penetration in order to ensure that users had both available to them in order to make a fair comparison."

OpenSignal said that the reason there may be a stronger correlation between screen size and data use over Wi-Fi is that places with Wi-Fi are often those where users have more choice in how to access the Internet. "For example, they may have access to a PC or Internet TV and in these cases it appears to be screen size that is the defining factor in whether they choose to remain mobile," OpenSignal said. "On the flip side to this, our data suggests that, when on the move, people treat their mobile devices in much the same way, consuming approximately the same amount of data. When on the go, people use their cell phone for their immediate needs and there is no trade-off in utility based on screen size because of the lack of alternative options to trade off to."

The study has several interesting implications. More and more high-end devices are being launched with larger screen sizes (the Samsung Galaxy Note II has a 5.5-inch diagonal screen, the Samsung Galaxy S4 has a 5-inch screen, the HTC One has a 4.7-inch screen and the Nokia (NYSE:NOK) Lumia 920 has a 4.5-inch screen). According to the study, as screen sizes continued to increase, so will average data usage (all of those devices run Android, except for the Lumia 920, which runs Windows Phone 8). 

Further, as carriers continue to deploy their LTE networks, they will likely continue to encourage data consumption--especially video--to reap data revenue and recoup their network investment costs. Carriers, therefore, are likely going to gravitate toward supporting devices that will encourage data consumption, which means larger-screen devices will likely become the norm.

The study is contradictory in some ways to one released in January by network technology firm Arieso. That study found that smartphone users are actually consuming more data on a per-user basis than tablet subscribers for the first time. The report was the third-annual study from Arieso analyzing mobile network trends. Arieso, which advises carriers in the United States, Europe and Asia, as well as companies including Ericsson (NASDAQ:ERIC) and Nokia Siemens Networks, found that out of the top 10 most data-intensive devices (excluding USB modems) six were smartphones, three were tablets and one was a phablet. The tablets on the list were at Nos. 4, 8 and 9.

For more:
- see this Open Signal report

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