How to Validate Machine Learning Models: ML Model Validation Methods
Developing the machine learning model is not enough to rely on its predictions, you need to check the accuracy and validate the same to ensure the precision of results given by the model and make it usable in real life applications. For machine learning validation you can follow the technique depending on the model development methods as there are different types of methods to generate a ML model.
Choosing the right validation method is also very important to ensure the accuracy and biasness of the validation process. As if the data volume is huge enough representing the mass population you may not need validation. But in real-world the scenario is different as the sample or training data sets we are working may not be representing the true picture of population.
Here you need to use the right validation technique to authenticate your machine learning model. Though, there are different types of validation techniques you can follow but make sure which one suitable for your ML model and help you to do this job transparently in unbiased manner making your ML model completely reliable and acceptable in the AI world.
Machine Learning Model Validation Techniques
Holdout Set Validation Method
It is considered one of the easiest model validation techniques helping you to find how your model gives conclusions on the holdout set. Under this method a given label data set done through image annotation services is taken and distributed into test and training sets and then fitted a model to the training data and predicts the labels of the test set.
The portion of correct predictions constitutes our evaluation of the prediction accuracy. The known tests labels are withhold during the prediction process. Actually, experts avoid to train and evaluate the model on the same training dataset which is also called resubstitution evaluation, as it will present a very optimistic bias due to overfitting.
Cross-Validation Method for Models
As per the giant companies working on AI, cross-validation is another important technique of ML model validation where ML models are evaluated by training numerous ML models on subsets of the available input data and evaluating them on the matching subset of the data.
Basically this approach is used to detect the overfitting or fluctuations in the training data that is selected and learned as concepts by the model. More demanding approach to cross-validation also exists, including k-fold validation, in which the cross-validation process is repeated many times with different splits of the sample data in to K-parts.
Under this validation methods machine learning, all the data except one record is used for training and that one record is used later only for testing. And if there is N number of records this process is repeated N times with the privilege of using the entire data for training and testing. Though, this method is comparatively expensive as it generally requires one to construct many models equal in number to the size of the training set.
Under this technique, the error rate of model is almost average of the error rate of the each repetition. The evaluation given by this method is good, but at first pass it seems very expensive to compute. Luckily, inexperienced learner can make LOO predictions very easily as they make other regular predictions. It is a one of the best way to evaluate models as it takes no more time than computing the residual errors saving time and cost of evolution.
Random Subsampling Validation
Companies offering ML algorithm validation services also use this technique for evaluating the models. Under this method data is randomly partitioned into dis-joint training and test sets multiple times means multiple sets of data are randomly chosen from the dataset and combined to form a test dataset while remaining data forms the training dataset.
The accuracies obtained from each partition are averaged and error rate of the model is the average of the error rate of each iteration. The advantage of random subsampling method is that, it can be repeated an indefinite number of times.
Bootstrapping ML Validation Method
Bootstrapping is another useful method of ML model validation that can work in different situations like evaluating a predictive model performance, ensemble methods or estimation of bias and variance of the model.
Under this technique the machine learning training dataset is randomly selected with replacement and the remaining data sets that were not selected for training are used for testing. The error rate of the model is average of the error rate of each iteration as unlike K-fold cross-validation, the value is likely to change from fold-to-fold during the validation process.
Apart from these most widely used model validation techniques, Teach and Test Method, Running AI Model Simulations and Including Overriding Mechanism are used by machine learning engineers for evaluating the model predictions. However, these methodologies are suitable for enterprise ensuring that AI systems are producing the right decisions. Basically this technique is used for AI algorithm validation services and it is becoming hard-to-find better ways to train and sustain these systems with quality and highest accuracy while avoiding the adverse effects on humans, business performance and brand reputation of companies.