Researchers may not be as interested in collecting data from all participants on the same dates. One may seek to collect multiple weeks' worth of data from participants regardless of when participants start the project. This helps with data collection as it is often hard to start a study on the same date for all participants. The "Rolling Schedule" enables researchers to automatically collect, for example, 2 weeks' worth of data from participants, beginning whenever the participant starts the project.
This type of schedule accommodates:
(a) Time-based ESM or EMA surveys (sends signal to participants for a specific time in the day)
(b) Signal-contingent ESM or EMA surveys (sends signal to participants randomly within a time slot in a day)
(c) Event-contingent ESM or EMA surveys (allows participants to fill in a survey whenever they encounter an event in the day)
(d) All of the above in different combinations
The major thing to note is that "Week 1-Day 1" refers to when a participant enters the access code to start the project on their mobile device. Therefore, if a survey begins on Week 1-Day 1 (where the "Start" is on the scheduler), a participant starts receiving notifications to take surveys on the same day. It is possible for participants to miss surveys if they start the project past the time slot of the survey. For example, if a researcher sets a survey time slot to 9am-10am on Week 1-Day 1, a participant entering the access code and starting the project at 11am will miss the first survey time slot from 9am-10am. It is recommended that researchers start the project on Week 1-Day 2, the day after participants enter the access code to start the project.
One of the strengths of the Expimetrics platform is that all the scheduling will be conducted based on participants' time zones. For example, an 8am survey will be sent to participants at 8am regardless of which part of the world a participant is in. This is automatically handled through the Expimetrics participant-time algorithm.
Another strength of the Expimetrics platform is that mobile app notifications will be sent to participants for all date- and day-scheduled surveys. In other words, any survey scheduled within "Fixed" or "Rolling" schedules will have an app notification sent to participants to remind them that a survey is available for them to take. All app notifications are handled by the Expimetrics platform automatically.
All of a participant's surveys are automatically linked over time. When participants participate in a project which has multiple (scheduled) surveys, all the data are linked to the participant uniquely. Researchers do not need to include survey questions requesting researcher-assigned participant IDs in order to link surveys.