Tablet Devices for Offline CAPI - Overview
Tablet Devices for Offline CAPI - Overview
For Customers
Written by:
Ofer Heijmans - Dooblo
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Tablet Devices for Offline CAPI - Overview
Table of Contents
1
TABLET DEVICES FOR OFFLINE CAPI SURVEYS ........................................................... 3
1.1
OVERVIEW .................................................................................................................................. 3
1.2
TABLET SIZES .............................................................................................................................. 3
1.3
SCREEN QUALITY ........................................................................................................................ 4
1.4
CAMERAS .................................................................................................................................... 4
1.5
BATTERY POWER ........................................................................................................................ 5
1.6
MEMORY..................................................................................................................................... 3
1.7
CPU ............................................................................................................................................ 5
1.8
STORAGE – THE TABLET “HARD DISK” ........................................................................................ 5
1.9
SEMI RUGGED DEVICE (3.7”) ...................................................................................................... 6
1.10
POSSIBLE LOW-END DEVICES .................................................................................................. 6
1.11
POSSIBLE MID-HIGH RANGE DEVICES .................................................................................... 6
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Tablet Devices for Offline CAPI - Overview
1 Tablet devices for offline CAPI surveys
1.1 Overview
Android tablets come in all sizes and features. From very cheap low end devices to
full featured expensive high end devices. The following will detail some possible
options for low, mid & high end devices. Tablets vary mainly in the following:
 Size (3.5”, 7”, 10” and sizes in between)
 Screen quality
 GPS (yes/no)
 Cameras (No camera, forward facing or both forward and back facing)



Battery power
Storage
CPU power
1.2 Tablet sizes
There is a big distinction between the smaller 3.5” mini tablets and the other 7”+
tablets. The mini tablets while being less expensive usually come equipped with both
GPS and 2 cameras almost as a standard. However, for the larger tablets the
availability of GPS and cameras is very dependent on price. It’s therefore that if the
project requirements can endure smaller 3.5” tablets, it will provide for better
cost/benefits. For obvious reasons, smaller tablets will have smaller screens.
1.3 Internal Memory
Important: Please do not confuse Memory with Storage. Some device vendors will list
storage with descriptions that seem as if it is memory and confuse customers.
Internal memory is one of the most important factors when choosing a device for
tablet surveys. Complex surveys tend to use up memory and so it is generally not
recommended to get a device with less than 1GB of memory. The following is a list
of survey attributes that significantly increase the use of device memory:
 High quality images / videos




High number of images / videos
High number of quota definitions ( > 150)
High number of questions ( > 100)
Big answer lists for questions (> 300 answers)
If you expect running surveys that will feature one or more of the above attributes
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Tablet Devices for Offline CAPI - Overview
please consider to use a higher memory device. Following is a list of what would be
considered low, medium or high memory devices:
 Low: > 500MB
 Medium: 1GB
 High: 1GB and up
1.4 GPS
GPS is very important for CAPI as it forms the basis for quality control. SurveyToGo
will use the GPS to capture location information to allow quality control and
fieldwork departments to use this information to verify interviews were performed at
the correct place. There are 2 different GPS types:
1. Hardware GPS: This is what most people refer to as GPS. This hardware
receiver picks up the signal from satellites and determines the location with
great accuracy and without the need for a WIFI or a 3g connection. It is
present in most mid-high range devices and in some low-range devices.
2. A-GPS (Assisted GPS): This is a relatively new addition and this GPS will
receive its location from either WIFI or 3g networks. Ideally, a device would
have both hardware GPS and A-GPS which will allow the device to make out
its location based on hardware GPS if possible and when not possible use the
A-GPS instead. This is the case with almost all mid-high range devices. Some
low-cost devices will have only the A-GPS and not a hardware GPS which
means that if the device is not connected to the network no GPS location will
be captured. It is not recommended to get a device with only A-GPS.
1.5 Screen quality
When showing videos & photos, screen size and quality can make a big difference.
10” high-end devices will obviously provide the best combination of screen sizes and
quality. However, smaller 7” devices are also adequate in size to display images and
videos. As a rule of thumb, the lower end devices tend to have screens of less quality
so if displaying media is a high priority screen quality should be given attention.
1.6 Cameras
There are 2 types of cameras. Forward facing and backward facing. The forward
facing camera is used in video conferencing to shoot the face of the person using the
tablet. The backward facing camera is the one you use to take pictures of places.
Usually, on the lower end tablets, either no camera is present or a forward facing
camera only is present. If you need to take pictures of places/people on a regular
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Tablet Devices for Offline CAPI - Overview
basis, it is advised to choose a device with a backward facing camera.
1.7 Battery power
Battery power in tablets is affected from 3 main components:
 The battery size – the bigger the better
 CPU strength – the slower the better
 Screen size/usage – the smaller the better, the less time the screen is on, the
better.
Battery power is as far as we know not directly related to the cost of the device. There
are high end devices with small batteries and lower end ones with big batteries.
1.8 CPU
CPU power plays a big role when choosing a tablet for consumer use as games and
media rich applications eat up CPU making the device sluggish. When choosing a
tablet for CAPI tablet surveys CPU power is less of an issue although for certain type
of surveys you might want to consider more powerful CPU based tablets. Standard
CAPI surveys of under 100 questions with little or no logic in them should run fine on
any CPU. If you are planning to run surveys that contain the following attributes, you
might want to use a faster CPU based device to prevent noticeable degraded
performance that causes the device to seem sluggish:





Lots of logic code and heavy use of functions
Lots of Media (Videos, Images, Sounds)
Querying big external data lists from inside the survey code
> 50 quota definitions
> 150 questions
1.9 Storage – the tablet “Hard disk”
Storage is usually not something you need to consider if you are planning on running
tablet surveys that do not capture or make use of media such as videos, photos or
sounds. If you are planning on capturing or displaying media, you should run some
calculations to make sure the device storage is suitable for your needs. You need to
take the following factors into consideration when doing the calculations:
 Size of media captured per interview
 Number of interviews before syncing (the media is removed after syncing).
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Tablet Devices for Offline CAPI - Overview
1.10 Semi Rugged device (3.7”)
Device name
Price
Motorola Defy Mini XT320
~$200
Features
Comment
1.11 Possible low-end devices
Device name
Price
Archos 70 Internet Tablet 8 GB -
$170
Features
Comments
Android 2.2 1 GHz
Lenovo Ideapad A1 22282MU 7-Inch
$199
Tablet
ViewSonic ViewPad 7e 4 GB
$170
ViewSonic ViewPad 10s 16 GB
1.12 Possible Mid-High range devices
Device name
Price
Samsung Galaxy Tab 7.0
$350
ViewSonic ViewPad 10s 16 GB
$250
Motorola XOOM With Wi-Fi 32 GB
$350
Acer ICONIA Tab A500-10S16u 16
$300-
GB
$400
ASUS Eee Pad Transformer TF101 16
$350
Features
Comment
GB
Samsung Galaxy Tab 10.1 WiFi 16
$350-
GB
$400
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