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Mobile Data Collection toolbox

4.2.1 Choosing your mobile device


What criteria should you look into ? Wether you decided to use smartphones or tablets, the selected device has to follow the below recommended features and settings in order to meet your Mobile Data Collection (MDC) needs.

Warning: Whatever device you select, make sure to use the same one for all your teams and for the whole survey in order to facilitate the MDC. The purchase of devices will very likely serve for several surveys, make sure the choice is based on a broad analysis of the needs at delegation level.

How to choose your device?

Your device must run on Android as ODK environment tools including ODK collect can only run on this operating system. It is recommended to use the combination of ODK collect application and KoBoToolbox (server). This choice may however not be adequate to every context (i.e. very sensitive information). Besides, Android phones are usually:

  • More affordable (Both for the device and potential accessories);
  • The operating system is more open for users (to access files, choose among more applications, etc.) and developers (open source development);
  • Available with most brands and models;
  • More widely spread and used in developing countries thus easier to handle for teams.

The right choice of the brand and the model of a MDC device depends on various project and country-related constraints as explained hereafter:

Constraints Tips and advices
Operational If smartphones or tablets are already available at country level, it’s recommended when possible to use the same type of device as it will facilitate their appropriation by teams and ease the resolution of technical problems.
Financial 50USD smartphones are now available in most of countries. However, the durability of such devices is generally shorter than for smartphones ranging between 150USD and 200USD. This should be taken into account according to the planned duration of use (for several surveys/projects) and the corresponding return on investment.
Specific Needs GPS, camera, barcode scanner, possibility to install specific applications, etc… A list of all features required for your MDC has to be done before choosing your device.

In any case, systematically test the device at least a couple of days in real conditions (majority of sellers accept to lend one unit if you plan to purchase a batch of them), especially the specific features needed for your project, to avoid unpleasant surprises (especially before purchasing a large quantity of devices).

You will find below a list of important criteria which should be considered when purchasing smartphones/tablets. It is also advised to choose a model recommended by HQ or another country-office.

Warning: The recommended below “figures” are applicable to 2015-2016 smartphones or tablets.

Criteria Details
Battery life (for each cycle and over the device life)
  • Battery quality should be considered at the time of purchase but also after a few months/years (quality of the battery being “included” in the price of the device…)
  • Minimum recommended capacity: 2000 mAh with an “external battery pack”
  • Battery life also on device settings, design, usage etc.
Display size and keyboard usability
  • Keyboard minimum recommended display size: 4.3” – desirable 5”
  • Depending on the type of survey: a lot of “open” questions requires a larger screen size as well as more user-friendly on-screen keyboard but a too large screen is also not handy for enumerators!
  • Ergonomics of the device and its keyboard should be systematically tested (in real situation i.e. standing position, device in one hand, entering open questions…)
  • A key element as enumerators are standing up all day long carrying the device in their hands
  • Maximum recommended weight for “standing face to face” surveys: 200 gr
  • A key element in many contexts as for MDC during the rainy season, in the “bush”, in dusty areas, including motorbikes travel, etc.
  • Some devices are specifically ruggedized to be used in harsh environment (IP 65 to IP68 for dust and liquid resistance )
  • Do not forget to purchase additional accessories if necessary (see below)
Availability over time of device series
  • It is always easier to use a same series/range of devices (installations and trainings are easier to implement as well as remote resolving of problems).
  • When purchasing devices, priority should be given to well-known brands, series and models as they are more easily repairable.
Enriched data collection
  • GPS accuracy and needed time to find satellite signal (if required
  • Do not forget to test GPS accuracy and needed time to determine the position in representative places where surveys will be carried out (e.g.without 3G)
  • Quality and resolution of the camera: Minimum recommended resolution: 5 Mpx with flash (to take indoor pictures)
  • The device should be able to run a barcode scanner application (if required)
  • Do not forget to test camera quality for reading barcode and QR code
Connectivity (GSM, 3G…)
  • Check the compatibility of GSM / GPRS / EDGE / UMTS (3G) frequency bands according to your country (especially in case of imported devices from HQ or another country)
  • If a GSM connection is required, devices with dual-SIM card could be useful (especially in countries where coverage is uneven or unreliable)
USB connection
  • Check the connectivity with a USB cable in case data collected can’t be transferred wireless (Wifi/3G problems)
Standard version of Android OS
  • To avoid problems when installing apps, it is important to always purchase devices with a well-known version of the operating system
  • Minimum recommended Android Version: 4.1
  • Sufficient internal memory and dedicated card slot (to add a microSD card in order access or store more data like pictures)
  • Minimum recommended internal memory: 8 GB
Chipset and RAM
  • Minimum recommended RAM: 1 Go
  • Minimum recommended chipset: Quad core 1,2 GHz

Do also not forget to purchase also all the required adapted accessories (the need for accessories varies according to your context), such as:

  • Protective case (mandatory in all contexts);
  • Glass screen protector (mandatory in all contexts);
  • Neck strap (convenient for enumerators for surveys with smartphones, reduced risk of breaking the device);
  • USB cables;
  • Chargers (logical, with car adaptor…);
  • Portable charger (such as power bank) to charge devices when reliable power source isn’t directly available;
  • External SD card.
  • SIM cards if the connexion is good in the country and you would like submissions to be made through 3G rather than Wifi

Finally, when you have made your choice, to facilitate device management, we recommend that you:

  • Systematically test the model at least a couple of days (some providers accept to lend one unit if you plan to purchase a batch of them) to avoid unpleasant surprises (especially before purchasing a large quantity of devices).
  • Purchase devices per batch of same devices (rather than buying them one by one within different series)

Ensure you do not lose anything in terms of “Do no harm” principles by using electronic data collection

  • Examine whether using mobile devices will not create any data protection issues in your context – i.e. using mobile devices during interviews with children or vulnerable populations can be ethically questionable; but there are many places where they can also be perceived as tracking tools (i.e. Syrian context, Khost in Afghanistan…),
  • Ensure the consent you ask of respondents (for a survey) includes the fact that a mobile device will be used, giving the possibility for an enumerator to also use paper rather than mobile in case the interviewee refuses the use of MDC,
  • Check that the different tools that you use include the security features (such as encryption, relevant access rights etc.) that are deemed necessary

Smartphones VS Tablets

Smartphones and tablets can equally be used for Mobile Data Collection (MDC) depending on contexts and survey specificities. The below table may help to choose between smartphones and tablets:

Advantages of smartphones Advantages of tablets
  • Usually less expensive (better features/price ratio)
  • Lighter to move (e.g. with neck strap) and to carry (less bulky), particularly for surveys where enumerators spend most of their time standing up
  • More discreet (in terms of image
  • Better battery life
  • Better camera
  • Suitable screen size for most of the surveys
  • Better connectivity and geo-location (GPS, GSM, 3G, 4G etc.) at equivalent prices
  • Larger screen size: for complex surveys (easier reading and data entry) or survey carried out indoor
  • Less likely to be considered as a GPS in the contexts where having GPS is a problem
  • In some contexts, less easy to re-sell and therefore less risky of being stolen

If you chose a tablet make sure to check if:

  • It can record GPS locations (if required)
  • It has a SD card slot (if required)

Benchmark of smartphones and tablets

Smartphones and tablets have become an indispensable part of field operations worldwide, whether it is to respond to emails, to update team members via WhatsApp, or to collect data quickly and accurately. But the question remains: which phone or tablet will do the job when taken to the field for MDC? A comparison of Android phones and tablets for Mobile Data Collection done by CartONG & UNHCR in 2017 is available here. The findings of this benchmark are from 2017, so the characteristics of the devices may be outdated but there are a few elements in terms of criteria that can be of interest for organisations wishing to select their mobile device today. In this study we looked at these four focus areas:

  • How well can the device read QR codes and barcodes?
  • Can GPS data be collected without a SIM card?
  • Can the device be used as a wifi hotspot, even without a SIM card?
  • How well does the device withstand shocks, water and dust?

Whatever the choice you make we make these two recommendations for everyone working on mobile data collection:

  • If you buy phones, make sure to buy the same make and model for everyone. Different phones increase the time needed for technical support and training significantly.
  • If you are planning to bring phones to the field, make sure to familiarize yourself with the relevant customs regulations before getting on the plane. Nothing is more annoying than having your phones stuck in customs for weeks, while you are trying to sort out the paperwork.