Glance at any major smartphone line, and you'll find a similar pattern: Screen sizes are getting bigger, year after year, model after model.
Let's start with an audit of the world's most famous Android smartphone line--just look at those Samsung phones inch upward in the first chart below. Not to be outdone, HTC has kept pace with Samsung's escalating screen sizes, and Nokia has followed industry trends for its Lumia line as well.
Even Apple--which once described its 4-inch iPhone's screen as a "dazzling display of common sense"--appears poised to follow its rivals. The chart below illustrates a lukewarm interest in larger displays, but rumors are leaning toward the introduction of a 4.7-inch iPhone 6 later this year.
Larger phones: Yep, this is happening
It's also possible that just the flagship phones are getting bigger. To determine the breadth of the trend, I calculated the correlation between release date and screen size for over a thousand phones. The chart below shows several hundred of the most popular.
As you can see, the trend goes far beyond iPhones and Galaxies. There's a strong correlation between release date and smartphone screen size.
Before 2011, nearly every phone on the market measured between 2.5 and 4 inches. Since 2013, sub-4-inch phones have nearly disappeared. This graph paints a vivid picture:
So what's going on here? Why are phones turning into tablets? There's certainly more than one possible story behind this trend. I've distilled the data into five different scenarios, ordered from least to most likely.
Scenario #1: We're witnessing a marketing gimmick, played out over five years
No matter how many flashy software features smartphone developers bake into a new products, nothing grabs attention like new hardware design, particularly if there's a bigger display in the mix.
The iPhone 5 debuted with LTE support and a new A6 chip, but the updated screen size won every headline. Customers loved the 2013 HTC One's 4.7-inch screen, but the company couldn't resist adding another 0.3 inches to the M8. Then there's Samsung, which followed through on its "Next Big Thing" marketing campaign by steadily increasing screen size on the Galaxy S line, from 4.8 inches (S III) to 4.99 inches (S4) to 5.1 inches (S5).
It's a tidy little theory, but in the end it's only a theory. There are too many moving parts to conclude that rising screen sizes are all one big marketing strategy, even if bigger screens seem to be selling more phones. The case against Samsung looks strongest, but it's still too anecdotal.
Scenario #2: Apple got screen size wrong
When Apple introduced the first iPhone in 2007, the industry scrambled to replicate almost every aspect of Apple's design--from the app-icon interface and visual voicemail to the keyboard-less hardware and 3.5-inch screen size. For those first few years, it seemed that Apple could do no wrong.
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