---
title: lossKey
framework: createml
role: symbol
role_heading: Type Property
path: createml/mlprogress/losskey
---

# lossKey

The key that accesses the training loss value.

## Declaration

```swift
static let lossKey: ProgressUserInfoKey
```

## See Also

### Accessing assessment metrics

- [accuracyKey](createml/mlprogress/accuracykey.md)
- [validationAccuracyKey](createml/mlprogress/validationaccuracykey.md)
- [validationLossKey](createml/mlprogress/validationlosskey.md)