---
title: validation
framework: createml
role: symbol
role_heading: Instance Property
path: createml/mldecisiontreeregressor/modelparameters-swift.struct/validation
---

# validation

Validation data.

## Declaration

```swift
var validation: MLDecisionTreeRegressor.ModelParameters.ValidationData { get set }
```

## Discussion

Discussion The default is .split(strategy: .automatic), which automatically generates the validation dataset from 0% to 10% of the training dataset.

## See Also

### Accessing parameters

- [maxDepth](createml/mldecisiontreeregressor/modelparameters-swift.struct/maxdepth.md)
- [minChildWeight](createml/mldecisiontreeregressor/modelparameters-swift.struct/minchildweight.md)
- [minLossReduction](createml/mldecisiontreeregressor/modelparameters-swift.struct/minlossreduction.md)
- [randomSeed](createml/mldecisiontreeregressor/modelparameters-swift.struct/randomseed.md)
- [validationData](createml/mldecisiontreeregressor/modelparameters-swift.struct/validationdata-swift.property.md)