Participant Guide for the SMAAT Mobile App

Installing the app

The SMAAT app is available from the App Store (iOS) and from Google Play (Android). The app is available in 16 languages; the language can be changed in Settings.

Creating an account

When the app is opened without an account, it shows the Create Account screen. The fields are:

• Username. If the name is taken, the app suggests alternatives.
• Email (optional). An email address is needed to reset a forgotten password, to receive study notifications by email and to withdraw payments from the Wallet.
• Password (at least 8 characters) and Confirm Password.
• Date of birth (YYYY-MM-DD), required. It is used only to confirm the minimum age. People under 13 cannot create an account.
• Parent/guardian email, shown and required for people under 16, so that a parent or guardian can give consent.
• An optional switch to share device and diagnostics information (device model, operating system, screen). It is off unless switched on.
• Agreement to the Terms and Conditions.

Sign Up creates the account. An existing account is opened with Login. Forgot Password? sends a reset link to the email address of the account, so it works only for accounts with an email address.

Finding and joining a study

The Find a Study screen opens from the Overview tab or from More → Find a Study. It has five tabs:

• Code: enter the study code from the research team and tap Join.
• QR: scan a study QR code with the camera.
• Search: search public studies by name.
• Email: enter the email address to which an invitation was sent and tap Validate to list the matching studies.
• Invitation: enter a three-word invitation code (for example "happy blue fish") and tap Validate.

A study link from the research team opens the study directly in the app. A link can be used before an account exists. In that case the last onboarding step, "Create or Access Your Participant Account", offers Sign Up and Login.

Onboarding steps

Joining a study runs through a sequence of steps with a progress indicator and the buttons Back, Next and Finish. Steps that a study does not use are skipped.

1. Welcome: the study and the researcher with contact details.
2. Prescreening, if the study uses it: a few questions on eligibility, background, quiet times and preferred times. A person who does not qualify sees the study's message and, where offered, can leave an email address with Join waitlist.
3. Study information: the study code, length and recruitment dates. If the study asks for it, the participant enters a participant code, or enters or selects a group code, here.
4. Informed consent: the consent sections of the study, the expected time commitment when the study states one, and the button I Agree. If the study collects location, motion or health data, a separate box asks for explicit consent to these sensitive data.
5. Permissions, if the study needs any: notifications and sensor permissions. Some studies require all permissions before joining.
6. Account, only when the participant is not logged in.

The study screen

The app has three tabs at the bottom: Overview, Surveys and More. The Overview tab shows each joined study with:

• the study title and contacts;
• notices when participation is paused, when the study is paused or when it has ended, and a Permissions needed notice when a required permission is missing;
• Start survey cards for surveys that participants may start on their own;
• streak, points, level, leaderboard and progress, when the study uses gamification;
• the Messages card, which opens the conversation with the research team. Announcements from the researcher can arrive there too and can be answered;
• the buttons Permissions, Info, Upload (for studies that collect background data; it shows the data collection and sync status) and My Data (when the researcher allows participants to see charts of their own responses).

Permissions lists the permissions the study needs, grouped into notifications, foreground and background sensors and health data, with a count of granted permissions. Participants can also opt in to receiving the study's notifications by email (after confirming the email address) or by SMS (after verifying a phone number with a 6-digit code).

The Info screen

Info shows the study description ("About this study"), the participant's enrollment details (participant code, group code, study code, enrollment date), the researcher, and the informed consent sections. It also has two buttons:

• Pause data collection stops notifications and passive data collection without leaving the study. Data collected so far are kept. Resume data collection continues participation. The researcher sees the participant as On Hold while paused.
• Leave Study withdraws from the study after a confirmation. Leaving cannot be undone. If permissions or background tasks such as location tracking are active, the app first lists them and explains that leaving switches them off.

Completing surveys

The Surveys tab lists the survey prompts of one day. The arrows and the date button switch to another day. Each prompt has a status: Sent (open), with the time left until it closes, Completed, or EXPIRED ("Availability window closed"). Open starts a survey and View shows a completed one. By default the list shows only prompts whose time has come. Some studies also show upcoming prompts. For studies with encrypted responses, a completed survey shows a note that only the researcher can decrypt the answers.

Stopping a cognitive task part-way

Some surveys contain cognitive tasks, such as reaction-time tasks. A task can be stopped before its end with the ✕ on the task screen or, on Android, with the back button. The app asks "Stop this task?" and explains that the answers so far are saved and marked as stopped, and that the task cannot be continued later. Continue task returns to the task; Stop task ends it. The question then shows "Stopped" with the number of trials saved, and the survey continues with the next question.

The More tab

The More tab holds Find a Study, Wallet, Previous Studies, Settings, About and Sign out.

Wallet

In studies that pay participants, earnings appear in the Wallet: the Available balance, the amounts earned and withdrawn, and a history of transactions (survey payments, compliance bonuses, bonuses from the researcher, withdrawals). Withdraw asks for an amount and a payout method. Withdrawals require a verified email address (Settings).

Previous Studies

Studies that the participant has completed or left are listed here in two sections, Completed Studies and Withdrawn Studies, with the study details and the participant's codes.

Settings

The Profile Settings screen has:

• Username and Email (a new email address is confirmed through a link sent to it);
• a phone number for SMS notifications, with the country code, confirmed with a verification code sent by SMS;
• Password;
• Language;
• the home screen background of the study screen;
• Lock app with biometrics: the app asks for Face ID, Touch ID or the device passcode on launch and after 5 minutes in the background.

Save Changes stores the settings. Delete Account opens a separate screen. Deleting the account leaves all active studies, deletes the data stored on the phone, and erases the account's study participations, survey responses, sensor records and files on the SMAAT servers. Deletion cannot be undone, and the researchers no longer have access to that participant's data.

Signing out

Sign out asks for confirmation. Signing out removes the study data from the phone: responses that have not yet synced, saved survey progress, cached location and health data, and study encryption keys. Background tracking stops. To continue a study, sign in again and re-enable the permissions.

More help

Questions about a particular study go to its research team, through the Messages card or the contact on the Info screen.