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Understanding the Validation Dataset for Model Tuning

In this lesson, we will explore the concept of a Validation Dataset, which is used to assess and fine-tune the performance of machine learning models.

A validation dataset is crucial for ensuring that a model does not experience overfitting, and helps in selecting the optimal model.

Overfitting occurs when a model is too tailored to the training data, causing it to perform poorly with new data.


Once a model has learned patterns using the training dataset, the validation dataset is used to verify if the model can generalize properly.

The role of the validation dataset is to assess whether the model works well not only on the training data but also on new, unseen data.


Role of the Validation Dataset

The validation dataset acts as an intermediary stage, checking and adjusting the model's performance between the training dataset and the test dataset.

For instance, a validation dataset for an AI model that classifies dogs and cats might be structured as follows:

  • Inputs: Images of dogs and cats not included in the training dataset

  • Labels: Information indicating whether each image is of a dog or a cat

During training, the validation dataset is used to monitor the model's performance and adjust the training process to prevent overfitting.


Characteristics of an Effective Validation Dataset

For a validation dataset to be effective, it should adhere to the following guidelines.


1. Separate from Training Data

Validation data should be new data that does not overlap with the training data.

If validation is performed using the same data as the training data, it becomes impossible to verify the model's ability to truly generalize.


2. Sufficient Data Volume

The size of the validation dataset should be roughly 10-15% of the total dataset.

If too small, it can be challenging to accurately assess the model's performance, whereas if too large, there may not be enough data left for training.


3. Inclusion of Diverse Data

The validation dataset should include a variety of input data.

For instance, when validating a model that classifies dogs and cats, it is beneficial to include images of dog and cat breeds not present in the training data.

This way, you can check whether the model can accurately categorize truly new data.


After optimizing the model using the validation dataset during the machine learning training process, the test dataset is used for the final evaluation of the model's generalization performance.

In the next lesson, we will explore the test dataset in more detail.

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