Feature engineering is an extremely useful practice in machine learning where it can help to sensibly represent and process raw input data into more useful features.

Feature Engineering is about more than just collecting data, it’s about converting your raw data into features that will help improve your model.

In this blog post, we will learn what feature engineering is, the tools and techniques, and some fascinating real-world examples to help you implement the concept of feature engineering in your projects.

What is Feature Engineering?

Feature engineering is a machine learning technique that leverages data to create new variables that aren’t in the training set. It can produce new features for both supervised and unsupervised learning, with the goal of simplifying and speeding up data transformations while also enhancing model accuracy.

In the context of machine learning, feature engineering is the process of using domain knowledge to identify relevant features for modeling.

This includes,

  • Transforming raw data into features that are more suitable for modeling
  • Selecting relevant features from existing data
  • Creating new features based on existing features

Feature engineering is a key part of the modeling process and can have a significant impact on the performance of a machine learning model.

Data pre-processing is a critical step in machine learning that helps to clean up and organize the data, making it more useful for learning algorithms.

This process can involve, for example, transforming text data into a numerical form, removing noise and outliers from data sets, or standardizing data across different scales.

Importance of Feature Engineering

Feature engineering is an art of its own. There are numerous ways to use data, and it depends on the business or organization which factors should be used. This technique helps to bring out the best models by finding relevant relations between various factors.

The process also helps in saving a lot of time and money when you have accurate results. Typically, Feature Engineering is followed by a process called feature selection where irrelevant features are left out of the model-building exercise.

In addition to improving the accuracy of machine learning models, feature engineering can also help reduce the amount of data required to train models.

By developing features that are more informative and effective, data scientists can often use fewer data to achieve the same level of accuracy. This can be especially important when working with large datasets, or when data is scarce.

Furthermore, by carefully designing features, data scientists can help machine learning algorithms learn the underlying relationships in data more effectively, and create more robust and effective models.

Benefits of Feature Engineering

Feature engineering is the process of using domain knowledge to extract features from data. This can be done manually or using automatic feature extraction algorithms. The goal is to transform the data into a form that is better suited for machine learning.

Good feature engineering can result in improved performance from machine learning algorithms. It can also make the algorithms easier to train and interpret. In some cases, it can even allow the use of simpler algorithms.

The most prominent benefits of feature engineering include:

  • Feature engineering is vital because it allows you to create features that are relevant to your problem.
  • It allows you to transform raw data into a form that is more suitable for machine learning.
  • It can help improve the accuracy of machine learning models.
  • It can make machine learning models more interpretable, which is important for understanding how the models work.

Feature engineering is also an iterative process, and as we gain more experience with working with data, we can improve our feature engineering techniques. In this way, we can continue to improve the performance of our models and get the most out of our data.

Feature Engineering Techniques for Machine Learning

Feature engineering can be a very time-consuming and difficult task, but it is essential for getting good results from a machine learning algorithm.

There are many different techniques that can be used for feature engineering. Some of the most popular techniques include:


Imputation is the process of replacing missing values with estimates. In general, it is a powerful tool for dealing with missing values, and it can be a key ingredient in building successful machine learning models.

One of the advantages of imputation is that it can be used with any machine learning algorithm. However, it is important to note that imputation can only be used to improve the accuracy of your models; it will not fix underlying problems in your data. If your data is highly imbalanced, for example, imputation will not be able to help.

If you’re working with missing data, imputation is a technique that you should definitely be aware of. It can be a valuable tool for increasing the accuracy of your machine learning models.

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Handling Outliers

Feature engineering involves the manipulation of data in order to produce more accurate predictive models for machine learning. It can be used on multiple scales and has a wide range of applications.

Handling outlier observations well can mean the difference between an accurate model and a poor performing one, as well as an improvement in overall model quality.

There are a few different ways to handle outliers when building machine learning models.

  • One way is to simply remove them from the data set. However, this can sometimes be problematic if there are a lot of outliers, or if they are truly representative of the data set.
  • Another way to handle outliers is to transform them. This can be done by taking the log of the data, or by using some other transformation that makes the data more uniform.
  • Finally, the last way to deal with outliers is to use a robust regression technique. This is a technique that is designed to be less affected by outliers in the data.

In general, it is often best to try a few different techniques for dealing with outliers and see which one works best for your data set and your machine learning algorithm.

Log Transform

The log transform can be used to transform data that is skewed. This can be done by taking the natural logarithm of the data values. It will often result in a more symmetrical distribution of data.

The log transform can also be used to reduce the range of values in the data. This can be helpful when working with large datasets. By reducing the range of values, the data can be more easily processed by machine learning algorithms.

The log transform can also be used to improve the interpretability of machine learning models. By transforming the data, the relationships between features and target values can be made more clear. This can be helpful when trying to understand how a model makes predictions.


Feature scaling is the process of normalizing the values of your features. This is important because many machine learning algorithms require that the input features are scaled to a specific range.

Normalizing your features is an important technique for machine learning algorithms. Being able to scale a feature allows for easier feature comparisons. You may have one set of features that are not very helpful, but if you scale them appropriately, you may find that they are actually more useful than other, un-scaled features.

Each of these techniques can be used to improve the performance of your machine learning models. However, it is important to remember that there is no one-size-fits-all solution. The best approach will vary depending on the type of data and the specific problem you are trying to solve.

Best Tools For Feature Engineering

When selecting features from new data sources, there are many tools that can be used, but each has its own strengths and weaknesses.

Let’s have a look at some of the features of engineering tools that you can use to develop features effectively.

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Featuretools is a framework for converting data into feature matrices that are suitable for machine learning. By automating the process of generating features from existing data, it streamlines your data processing and power tool set.

It was created to bridge the gap between choosing features from within the tools that are already in your toolbox and ensuring that you have chosen the most accurate and useful features.


AutoFeat is an automated linear prediction model optimizer with built-in feature engineering and selection.

AutoFeat automatically selects the best available feature to predict each target variable, by considering several factors:

  • The number of input variables
  • The unit weight associated with each variable
  • The amount of data in each variable
  • The Granularity level of the selected output variable

It can automatically generate features from data, optimize features, and help with feature selection.


tsFresh is a python package used for time series analysis. It calculates a huge number of time series characteristics, or features, automatically.

These features can be used in regression and classification tasks to assess the explanatory power and significance of such traits in the task at hand. tsFresh supports a wide range of functions including exponential smoothing, moving averages, counting data groups, etc.


OneBM is a database development environment that provides several pre-packaged feature engineering tools. It can be used to alleviate the pain of writing custom features while supporting existing features with easy-to-use plug-ins.

It is rightfully one of the best feature engineering tools out there. It interacts directly with a database’s raw tables and gradually joins them, taking different paths on the relational tree.


The exploration and selection process is carried out by ExploreKit’s meta-learning system, which enables the identification of common operators to alter any feature. To overcome the issue of huge feature sets developed from different algorithms, different qualities are used to rank candidate features.

The meta-learning methods are trained with a small set of well-trained benchmark features and then run on large unranked datasets for which the performance can be evaluated directly.

Real-World Examples of Feature Engineering

It’s important to note that feature engineering is not limited to machine learning. It can be used in any data science project where the goal is to build a model that generalizes well from the data.

Feature engineering is a broad topic and the examples below just scratch the surface.

Text Mining

Text mining is the process of extracting information from documents, web pages, and other text-based media. You can use it to extract information such as the topics that are discussed in a document, the mood of the document, or who is mentioned in the document.

Image Processing

Image processing is the process of converting images into data that can be used by computer programs. Image processing can be used to solve a wide range of problems, such as object detection, image recognition, and medical imaging.

Social Network Analysis

Social network analysis is the process of analyzing the relationships between people, brands, or other entities through a visual representation of those relationships. You can use social network analysis to find insights or patterns in your data.

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In summary, feature engineering is a very important process to consider in machine learning and AI-related technologies. Since most data in business are interrelated and complex, finding the right data features can be tedious.

Therefore, it is important to gain some knowledge and practice with feature engineering techniques. The key to mastering feature engineering is to spend time practicing a variety of problems until the skill becomes effortless.

Having a better understanding of the various techniques used to generate data features in your studies on machine learning and other related branches will result in an effective outcome. These techniques will help you build informative data projects and shed more light on the inner workings of machine learning.

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Author's Bio

We strive to provide business professionals with the skills and knowledge necessary to increase work performance and drive greater return on investment for the global customers we support. Agilitics delivers customized technology and management training solutions to large corporations and government agencies around the world.