Machine Learning
Interview Questions
What is Overfitting?

What is overfitting and how do you prevent it?

Overfitting is a common problem in machine learning, where a model is too complex and has learned the training data too well, resulting in poor performance on new, unseen data. Overfitting occurs when a model tries to capture noise or random fluctuations in the training data, instead of the underlying patterns.

To prevent overfitting, several techniques can be used:

  • Cross-validation: This involves splitting the data into training and validation sets, training the model on the training set and evaluating its performance on the validation set. This helps to identify if the model is overfitting, as the validation set provides an estimate of how well the model generalizes to new data.

  • Regularization: This involves adding a penalty term to the loss function to discourage the model from becoming too complex. Common regularization techniques include L1 and L2 regularization, which add the absolute and squared values of the weights to the loss function, respectively.

  • Early stopping: This involves monitoring the performance of the model on a validation set during training and stopping the training process when the performance on the validation set starts to deteriorate. This prevents the model from continuing to learn the noise in the training data.

  • Data augmentation: This involves generating additional training data by applying transformations to the existing data, such as rotating or flipping images. This can help the model to generalize better to new data.

  • Dropout: This involves randomly dropping out some of the neurons in the model during training, which helps to prevent the model from becoming too dependent on any one feature.

By using these techniques, we can prevent overfitting and build models that generalize well to new data.