# correlation(type:predicate:) Returns a sample predicate that matches samples that contain correlated data. ``` static func correlation(type correlationType: HKCorrelationType, predicate: NSPredicate? = nil) -> HKSamplePredicate ``` ## Parameters `correlationType` A type that matches samples that contain a set of subsamples. `predicate` An optional predicate that further restricts the results that the query returns. ## Discussion Use this method to create an [`HKSamplePredicate`](/documentation/HealthKit/HKSamplePredicate) instance that you can use to query for [`HKCorrelation`](/documentation/HealthKit/HKCorrelation) objects. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)