You will need to contact us in order to have the SensorKit data export enabled for your project. Please refer to the Enabling SensorKit for your project article for further details on SensorKit.
SensorKit data are generated by a participant's Apple iPhone and paired Apple Watch. These data are available for data export in a JSON format within MyDataHelps Designer.
SensorKit export files tend to contain a large volume of data. Accelerometer and rotation rate sensors can generate > 3 GB of uncompressed data per day per participant. Other sensor data tends to be closer to 3.5 MB of uncompressed data per participant per day, which can still add up with high enrollment over a study’s duration (100 participants over a 60 day study duration would be 21 GB for that sensor alone).
Please note that Apple occassionally will report out duplicate samples. We strongly encourage project teams to review the data exports for duplicate samples (testing shows close to 1% of samples) and remove them from analysis.
Folder Structure
Exported SensorKit data is stored in the following folder hierarchy:
- Sample Type: Sensor type
- Device Type: iPhone or Watch
- Participant ID: The stable, automatically generated, internal system identifier for this participant.
- Device ID: Unique identifer for the participant's device
- Sample Timestamp: Timestamp for the sample
Data Fields
The following data elements are included within SensorKit data exports:
| Field | Description |
|---|---|
device |
Object of device details. |
systemVersion |
String representing the operating system version of the device e.g., "16.0." |
systemName |
String representing the operating system's name, e.g., "iOS." |
model |
String representing the type of device, e.g., "iPhone." |
name |
String representing the name of the device, e.g., "John's iPhone 13 Pro." Note: Apple has released an update that blinds the device name. You may find a more generic name in place here within data exports. |
samples |
Array of sample objects. |
sample |
Object of sample type data (see below table). |
timestamp |
The timestamp for each sample object, in ISO 8601 format. Includes timezone offset information. |
Apple Sample Type Data Fields
Please refer to Apple's documentation for each sensor's sample type data elements:
| Sensor | Sample Type |
|
Accelerometer |
CMRecordedAccelerometerData |
|
Ambient Light Sensor |
SRAmbientLightSample |
|
Device Usage Report |
SRDeviceUsageReport |
|
Keyboard Metrics |
SRKeyboardMetrics |
|
Messages Usage Report |
SRMessagesUsageReport |
|
On Wrist State (Apple Watch) |
SRWristDetection |
|
Pedometer Data |
CMPedometerData |
|
Phone Usage Report |
SRPhoneUsageReport |
|
Rotation Rate |
CMRecordedRotationRateData |
|
Siri Speech Metrics (iOS 15+) |
SFSpeechRecognitionResult |
|
Telephony Speech Metrics (iOS 15+) |
SFSpeechRecognitionMetadata |
|
Visits |
SRVisit |
The filename timestamps refer to the query timeframe, rather than the sample timeframe.