Castor Connect is Castor’s mobile application, enabling participants to complete their study assessments (‘surveys’) from the comfort of their personal devices. Castor Connect is a paid feature, please contact us via support@castoredc.com if you would like to enable this for your study.

If you are using web browser based surveys, below you will find a list of aspects to consider when developing a survey intended for a mobile phone or tablet.

Survey length
To ensure high participation rates, keep surveys short and simple. Many participants may wish to complete surveys whilst travelling and so it is important to make the survey forms as user-friendly as possible and consider the time needed to complete a study. It is advised to use short questions, so the respondents can see the complete question instantly without needing to scroll horizontally.

Grid fields
If possible, avoid using grid fields for mobile/tablet optimized surveys. Since they are formatted horizontally, the respondents will need to scroll before being able to see the next question. We recommend splitting these into separate questions for better user experience.

Option groups
Castor EDC has three option group fields: dropdown menus, radiobuttons, and checkboxes. Vertically formatted radio buttons and checkboxes are well suited to be used on mobile devices. Dropdown menus might not be the best option, since the respondents may need to click and scroll to see all options. However, in some situations they might be useful, since the option can be typed in the dropdown field and the option will appear. 

Images
Not all respondents have connection to a high speed internet connection on mobile devices, so consider this when considering using images in a survey. Additionally, images take up screen space - consider mobile users when including and sizing images in surveys and that this space may be better filled by survey questions!

Calculations
Not all mobile devices support JavaScript to full extent, that is why care should be taken when including calculations in a survey. Moreover, using complex calculations might lead to slow performance, and may use more mobile data to perform the calculation.

Open questions
With open-ended questions or large text fields, respondents will need to use a small keyboard of a mobile device which might not be always convenient and lead to some typos or mistakes.

Navigation bar
Keep in mind that the navigation bar can take up the majority of the screen in a survey, covering all the questions when opened. In this example, the respondent will have to switch between navigation bar and questions, which might not be ideal.

Dependencies
It may not be possible to completely avoid using dependencies in your surveys, however we advise using a simpler survey logic and to refrain from using many complex dependencies, as they might slow down the survey for mobile users. Consider that making all the questions in certain visits dependent may lead to the user viewing a blank page when the dependency is not met. 

Test using different devices
Always test your surveys before sending the invitations out to patients. It is possible to send a test survey to your own email and use the test survey to check performance on different devices. You can learn more about testing your surveys here.