Participant Registration

After creating a new study, the most important step is to enroll participants. Participants can join your study by downloading the Ethica app on their Android or iOS device and creating an account. There are 3 different ways for participants to enroll in your study:

  • Using the study URL
  • Using the study registration code
  • Using the study QR code.

You can find all these three information, i.e. URL, registration code, and QR code for your study, in the Design -> Basics page:

Enrolling Participants in Ethica Study

Using Study URL

The easiest way for participants to join your study is by using the study URL. Each study in Ethica has a unique URL, for example:

This URL points to the study's web page. You can think of this page as the study's landing page. When participants click on the URL of this web page on their smartphone, if they have the Ethica app already installed on their phone, they will be taken directly to the study's registration page inside the Ethica app. If they don't have the Ethica app installed, the link will open on their phone's browser and they will see the following dialog asking them if they want to enroll in the study:

Ethica Study Home Page in Android Ethica Study Home Page in iOS
Android iPhone

The participant can click on the Learn More button to read more about the study. In this case, they will still have the option to join the study through the Participate bar at the bottom of the screen.

Clicking on the Participate bar, or on the Participate button in the dialog will check whether the individual has the Ethica app installed. If yes, the Ethica app will be opened, and the person will be presented with the study's consent form. If not, the person will be taken to the Google Play Store or Apple App Store to install the Ethica app.

After finishing the installation and when the app is opened, Ethica will automatically detect the study which the user wanted to join and shows a custom welcome screen based on the user's study:

Using Study Background for App Branding in Android Using Study Background for App Branding in iPhone
Android iPhone

This allows you to brand the Ethica app per your study from the very first step. Additionally, there is no need for the user to enter any study code to join your study. As soon as the user logs in or signs up with the Ethica app, they will be presented with the study's consent form and can continue with the registration.

If your study already has a dedicated web page, you can modify it behave just like the web page shown above. This way, you can use your own web page's URL as the study's enrollment URL, and participants can register in your study by visiting your web page. Please contact Ethica Support for the required modification details.

The following video shows how the above process works on Android devices:

Using Registration Code

Each study has a unique registration code, which is a 3- or 4-digit number. Participants can enter this code inside the Ethica app to join your study. You can find the study's registration code by going to the Design  -> Basics page.

Assuming participants have already installed the app and logged in, they can enter the registration code in order to consent and join your study. The following video shows the steps involved in joining a study using the registration code:

Using QR Codes

Each study also has a unique QR code which points to the study URL. The enrollment using study URL was described above. QR codes are also the same, except that participants don't have to type the URL anymore. Scanning the QR code on the participant's device is the same as typing the URL in the browser's address bar. It opens the study's home page. When the link presented by the QR code is opened, depending on whether the participant has the Ethica app installed or not, they will be taken to the app to enroll in the study, or to the site to download the app first.

Enrollment Types

In Ethica, you have the option to specify who should be allowed to join your study. This can be done via the Enrollment Type attribute. You can set this attribute while creating a new study, in the Enrollment section. Alternatively, you can set this at a later time via Design -> Basics page.

Enrollment Type provides you with three options, each of them is explained below.


This option sets the study open to the public. Anyone can join the study as long as they have the study's registration code or the URL. You still can invite participants to join your study (see Invitation-based enrollment type), though holding an invitation is not necessary for participants to join.


Unlike Public studies, Invitation-based studies require individuals to be invited to the study before they can join. You will need to have the email address for the individuals you want to invite to the study. The invited individuals do not have to have an account with Ethica at the time of invitation, but they must create one using the exact same email address that you used in the invitation before they can use their invitation to join your study.

You can invite participants through Participation -> Invitation section. After opening this page you will see the option to invite participants, as shown below:

Inviting Participations to Ethica Study

Clicking on the Invite Participants button will open the Invitation List dialog:

Ethica Study Participant Invitation Dialog

Here you can enter the list of participants you want to invite. You can enter up to 50 names at once, each in a separate line. A given invitation must start with the email address of the invited participant. It can also include the first and last name of the individual, though it's not mandatory. The following lines each represent a valid invitation entry:,Bob,Smith

After you enter all the invitations, you can press Invite to create the invitations. Shortly after pressing Invite, Ethica will show another dialog with the result of the invitations:

Ethica Study Participant Invitation Result

As you can see in the image above, invitations are either created successfully or have failed because of one of the following reasons:

  • The individual you have invited is already registered with Ethica as a researcher. Ethica does not allow researchers to participate in a study (learn more why). If the email you have entered is for a researcher, you will receive an error here.
  • The individual you have invited already is part of this study. Therefore, you cannot invite them to join the study again.

Any successful invitation will be added to the invitation list on this page:

Ethica Study List of Invited Participants

The invitation list includes the prospective participant's email address, first and last name, the time she was invited, and an option to delete and revoke the invitation. It also shows the participant ID Ethica has assigned to this participant. Participant IDs are unique numbers which Ethica uses to refer to this participant throughout the system.

If while creating the invitations, you chose to send an email to participants about their invitation, Ethica sends them an email with the URL to join the study. The content of the email will be the following:

Email Subject:

Study invitation: {{Your study name goes here}}

Email Body:

Hi {{Individual's first name, if available}},

{{Your name goes here}} from {{Your institution name goes here}} has
invited you to join "{{Your study name goes here}}" research study.
Please click on the link below to download the Ethica app and join
the study:

{{Study URL will be placed here}}

If you don't have the Ethica app installed, the above link will ask
you to download it first.

If you have any problem with the link, you can just directly download
the Ethica app from Google Play or App Store, and after you register,
join study number {{Your study registration code goes here}}.

Also, please make sure you use {{Participant's email address which is
invited to the study goes here}} as your email address while registering.

Thanks for helping advance the science,
The Ethica Data team

When the participant joins the study, their entry will be removed from the Invitation list, and you can find them in the Participation -> Adherence list. In the "Adherence" page, and in any other part of the system, you will not see the email address or name of the participant. You can only see their Ethica ID. This helps to protect the participant's personal information.


If you do not want to enroll any new participant in your study, whether temporarily or permanently, you can set the study to Closed. This will prevent any individual, whether invited or not, to join your study. You can change the status of your study or Closed or from Closed to other states at any time.

Ethica Android and iOS App

Ethica provides a native mobile application for Android (available via Google Play Store) and iOS (available via Apple App Store). Participants can download the Ethica app on their smartphone, and use that to join your study.

Ethica for iOS supports iOS version 10 and above, which is reported to covers more than 95% of active iPhone devices. Ethica Android supports Android version 4.1 and above (API version 16+) which covers 99.5% of Android devices. While we acknowledge the likelihood of some participants with old smartphones not being able to download Ethica on their device, we believe the possibility of this causing enrollment challenges or introducing any selection bias is negligible.