Tablets vs Phones: Hardware Matters

by | September 12, 2011
Category: Blog

When people initially think of ODK (Open Data Kit) and Android-based data collection, their thoughts turn to mobile phones–but this is changing. The emergence of a rich Android tablet ecosystem over the past year has given surveyors even more choices beyond the 101 different Android mobile phones out there. Now, project planners must consider tablets, and with the announcement of a $200 tablet, they are a real and viable alternative.

To better understand the trade-offs between phones and tablets, we are using the HTC MyTouch 3G Slide and the Samsung Galaxy Tab 7.0 in our current pilot. Here are a few quick observations about each.

Device Size: Bigger Screen is Better

The biggest discerning factor between the devices is the size of the screen. The majority of our enumerators prefer the bigger screen because they can more easily manage the keyboard, read the text, and avoid accidental button-presses. This is especially that case for our older enumerators with deteriorated dexterity and eyesight.

On the back-end, we prefer the large screen size as well. During the device set-up and training, and now in daily use downloading data, we have handled the devices almost as much as the enumerators. The larger screen lets us navigate menus faster. When we have work to do with the tablets, we can easily lay them on the table side-by-side and duplicate the same process on them one step at a time[1]. But with the phones it is more difficult to do so, and we end up picking them up and conducting a procedure one phone at a time.

Our youngest enumerator does prefer the portability of the phone. The enumerators were given file folders to carry their device and back-up paper copies of the survey, but he prefers to just slip the phone into his pocket.

Battery Life and Charging

We designed the survey procedure to be very, very battery conscious given the poor battery life you often see with Android phones. We will discuss those precautions in another post, but they were adequate, and no device has yet run out of charge after a day’s use. The tablets do have a much better battery life, and we could probably get two days charge out of a device if we had to. Please note that we are using GPS twice during each survey and use up most of our battery that way.

The phones do have removable batteries, and we could cheaply purchase and provide back-up batteries that way, if needed. Tablet batteries cannot be removed, so you would have to rely on an external (and more expensive) battery back-up system. Also, the phones use the nearly universal microUSB cable, and the tablets have something that looks similar to (but isn’t) an iPod/iPhone/iPad cable, so getting a new charging cable would be much, much easier with the phones.


The phone has a slide-out hard keyboard that many people favor on phones, but in practice we are not using it for two reasons:

There is a glitch is the version of ODK that we are running (1.1.7) that causes ODK to crash if the keyboard is opened during the survey.
ODK doesn’t display well in the “landscape” mode that an open keyboard requires.
We were able to set the phone soft keyboard to display like a regular phone[2]. The enumerators prefer this because (1) they are not familiar with the QWERTY keyboard; (2) it means that each button is a little bigger on the screen; and (3) they have experience SMSing in this way.


We have not conducted extensive tests on the devices, but the screens of both devices remain relatively unscratched. The phones have fallen more than a meter onto concrete, and survived with nothing worse than scratches. We would guess the tablet would not handle a fall from quite as high. Both devices have high-density plastic screens (rather than the more shatter-prone glass).

Odds and Ends

The phones take SIM cards and our tablets do not (although some do). We are not transmitting the data over the GSM network, but rather uploading it in the office at the end of each day, so that feature is not valuable for us.

Regardless of the phone you choose, read up on the quality of its GPS chip/software. Both our devices have great GPS chips that pinpoint locations quickly; however, this author’s personal phone, the Samsung Captivate, has a horrible glitch and requires 5-10 minutes to triangulate a position.

The phones require microSD cards in order to run the apps we are using. They are cheap, but might be hard to find in a pinch in rural areas. Be prepared!

We have incredible sleeves for the tablets. They are rugged and smartly designed with a pull strap to remove the device from the sleeve. I can only hope that future tablets will have sleeves of this quality.


Despite the phone having more distinct characteristics in its favor, we are leaning toward the tablet for future deployments because of its superior battery life and bigger screen.

We plan to post a follow-up at the end of the pilot with a comprehensive chart tracking battery life, variations in survey length between the devices, and short video interviews with our enumerators on their preferences and thoughts.

[1] For example, with three devices side by side, we can hit the home button on each device, then the settings buttons, then the Airplane mode button, etc.

[2] For the letter “c” press the number 1 three times.

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