What is the correct screen size for a smartphone display?

Four inches is the wrong size?

Last year I read an article in Gizmodo entitled  "This Is Why the iPhone's Screen Will Always Be 3.5-Inches" which tries to explain why 3.5-inches is the perfect size. The statement was premised on how far your thumb can reach across the screen. The obviously flaw in the premise is that the article seems to assume the people all have the same sized of hands. 

There is no perfect screen size.

1. Bigger is better. Larger screens are more comfortable to read and manipulate. That is why we have tablets, and why tablets are popular. In the end, tablets are really just super sized smartphones. If there was no need for larger screens tablets would not be immensely popular. 

2. Bigger is better is relative. What is "big" is relative to how you use it. The iPhone screen always felt cramp to me. Coming from a QWERTY, I type with the phone in portrait mode. So I like my phones a bit wide. At the same time, I like to be able to make calls one handed, so I like to be able to read the top of the screen with my thumb. I used one thumb to select the users name on the number pad, and select the suggestions at the top of the screen with the same thumb. Larger 4.7 to 5-inch phones are a bit of a reach for me. People with larger hands, could manipulate a 5-inch phone as comfortably as I manipulate my 4.3-inch phone.

In my previous buyers guides, price was the basis for classifying phones. Phones today comes is a wider variety of sized than ever before. When I started this blog, a 3-inch touchscreen smartphone was small, and 4.3-inches was considered to be stretching the limits or ergonomics. Since than, size have grown even to a smaller 2.8-inches and grown to as big as 5.5-inches. Starting 2013, I will use size, compact (4-inches or less), mid-sized (over 4-inches but not over 4.5-inches), large (over 4.5-inches to 5 inches) and phone tablets (over 5 inches) as the bases for classifying phones. I think that size is becoming a more and more important consideration, as out favorite toys get super-sized.