Training and Testing Data in Machine Learning

[This article was first published on Data Analysis in R, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

The post Training and Testing Data in Machine Learning appeared first on finnstats.

If you are interested to learn more about data science, you can find more articles here finnstats.

Training and Testing Data in Machine Learning, The quality of the outcomes depend on the data you use when developing a predictive model.

Your model won’t be able to produce meaningful predictions and will point you on the wrong path if you are using insufficient or incorrect data.

Training and Testing Data in Machine Learning

You must comprehend the distinction between machine learning training and testing data in order to prevent this. Let’s get started without saying more.

What are the algorithms used in machine learning?

Training Data

Consider the scenario when you wish to build a model using a database. This data is split into two categories in machine learning: training data and testing data.

You provide training data to a machine learning model so that it can examine it and identify some patterns and dependencies. There are three primary traits of this practice set:


Typically, the training set contains more data than the testing set. The machine produces a higher-quality model as you feed it more data.

Upon receiving data from your records, a machine learning algorithm learns patterns from it and creates a model for decision-making.


The value of a label is what we attempt to anticipate (response variables). The response variable will be Yes/No for the cancer diagnosis, for instance, if we want to predict if the patient will be diagnosed with cancer-based on their symptoms.

Both labeled and unlabeled training data are possible. Machine learning can make use of both types in a variety of situations.

Case specifics:

Decisions made by algorithms are based on the data you provide. Make sure the data is pertinent and includes a variety of scenarios with diverse outcomes.

For instance, if you require a model that can evaluate possible borrowers, you must include in the training set the data you typically have on hand during the application process about your potential client:

1. Name and contact details, location;

2. Demographics, social and behavioral characteristics;

3. factors relating to website behavior or activity, conversions, time spent there, amount of clicks, and other things.

Why Do So Many Data Scientists Quit Their Jobs?

Testing Data

You must assess the machine learning model’s performance after it has been created. The AI platform evaluates your model’s performance using testing data, then modifies or optimizes it for more accurate forecasts.

The following qualities should be present in the testing set:

Unseen: The same data that was in the training set cannot be used again.

Large: The data collection needs to be substantial enough for the computer to make predictions.

Representative: The data should accurately reflect the dataset.

Fortunately, you can compare forecasts with actual data without manually gathering new data.

The AI is capable of dividing the available data into two sections, delaying testing while it is being trained, and then conducting tests to compare forecasts and actual outcomes on its own Although there are other alternatives for data splitting in data science, the most popular ratios are 70/30, 80/20, and 90/10.

With such a large data set available, we can determine whether or not predictions based on that model are feasible.

An Illustration of the Use of Training and Testing Data

The blind test is the name of the evaluation procedure used in these systems. AI divides the data it uses to create models in a ratio of roughly 70% to 30%, with the first figure representing training data and the second representing testing data.

The computer examines many metrics during training to determine how they affect the outcome. Additionally, it tries to estimate the score for test records and forecast the outcome during the blind exam.

It can be used with double-factor targets as well as numerous targets with unique ratios and stratifications.

The machine determines a unique index that gauges the model’s quality once it has been constructed and tested. Users can choose to develop a different scoring model or utilize this one.

Python is superior to R?

What Amount of Data Is Needed for Machine Learning

The machine should be able to learn if the training and testing sets are both sizable enough.

But exactly how much is enough?

Well, According to the platform you choose. To develop a model, some machines require at least 1,000 records. The data’s quality is crucial, though.

The unwritten guideline in the industry is to build a dependable model by combining X number of good records with 1,000 bad records. For instance, X loans with successfully repaid debts and 1,000 non-performing loans.

This is merely a rough estimate, though. Only by evaluating several possibilities will you be able to pinpoint the precise amount of records required for your particular scenario.

According to our experience, a good model can be created with just 100 records, though some situations require over 30,000 records.

You have endless opportunities to play with various types of data and create as many models as you like using GiniMachine, which we previously described.

However, the data needs for other platforms, such as Visier People or, can be different. When selecting a platform for making decisions, pay attention to these qualities.

Prediction Errors

The bias-variance tradeoff and the curse of dimensionality should be mentioned when discussing prediction models since they have an impact on the accuracy of predictions.

The bias-variance tradeoff, in a nutshell, is the balance between designing models that are either generic or too particular. High-bias models frequently oversimplify data and commit numerous errors in both training and test sets.

When we have insufficient data that is too general, this occurs. When teaching the model to distinguish between cats and dogs, for instance, you might provide just ten instances of fur length and color. You need to use more data and variables to solve this problem.

Furthermore, the model with a high variance does not at all generalize the data. As a result, it displays positive results on training data but negative results on test data. If you gave the model too much detailed, specific data, this outcome is plausible.

As a result, it is unable to recognize which features are most crucial and is unable to correctly anticipate using unobserved data.

Surprising Things You Can Do With R

Additionally, the abundance of features makes your model more complex and increases the risk of the curse of dimensionality. In this case, you must cluster specific features together and purge the dataset of extraneous data.

Using Data in Business

Machine learning and AI-based prediction tools have limitless potential. You can use them to analyze healthcare and agricultural data, evaluate new leads, decide which projects are most promising, grade credit applications, collect debts, automate hiring procedures, and estimate demand for your product.

The use of such a platform has no restrictions. The correct dataset will allow you to create the required model, begin scoring, and increase your business production.

If you are interested to learn more about data science, you can find more articles here finnstats.

The post Training and Testing Data in Machine Learning appeared first on finnstats.

To leave a comment for the author, please follow the link and comment on their blog: Data Analysis in R. offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)