What is Feature Engineering?
Feature engineering involves the selection, manipulation, and transformation of raw data into features used in supervised learning. The purpose of feature engineering is to improve the performance of machine learning algorithms by enhancing model accuracy on unseen data.
Examples of Feature Engineering
Feature engineering is a machine learning technique that leverages the information in the training set to create new variables. It simplifies and speeds up data transformations and can enhance model accuracy by producing new features for supervised and unsupervised learning. Some examples of feature engineering include:
1. Continuous Data
Continuous data refers to values that can take any value within a given range. Examples include product prices, industrial process temperatures, and geographical coordinates. Feature engineering can involve mathematical operations on these variables, such as calculating profit by subtracting warehouse price from shelf price or determining distance by measuring the distance between two locations on a map.
2. Categorical Features
Categorical features are variables that can take on values from a limited set or can only have a single value. For example, the ISO/IEC 5218 standard defines four genders: not known, male, female, and not applicable. Feature engineering can involve separating a categorical feature into a set of features or encoding it to represent numerical values.
3. Text Features
Feature engineering also involves converting text into numerical values for analysis. Text mining techniques often encode text data by word counts, where the occurrences of each word are counted and represented in a table.
4. Image Features
For machine learning analysis of images, feature engineering is used to appropriately encode image data. Techniques such as edge detection or extracting color histograms can be applied to extract meaningful features from images.
Why is Feature Engineering Important?
Feature engineering is important for improving the accuracy and predictive power of machine learning models. By selecting relevant features, dealing with missing data, encoding data, and normalizing it, feature engineering improves the quality of model outputs. It helps in making accurate predictions by providing the right input variables and removing redundant and irrelevant variables.
Feature selection, a part of feature engineering, helps limit the number of features to a manageable number while still allowing the creation of sophisticated and interpretable models. Understanding the relationship between features and the target variable through feature importance analysis can also guide feature engineering and eliminate irrelevant features.
Feature Engineering vs. Other Technologies & Methodologies
Feature Engineering vs. Feature Selection
Feature engineering involves creating new features from raw data, enabling the construction of more sophisticated and interpretable models. Feature selection, on the other hand, focuses on limiting the number of features while retaining the most relevant ones to improve model performance.
Feature Engineering vs. Feature Extraction
Feature engineering involves transforming raw data into features that better reflect the underlying structure of the data. Feature extraction, on the other hand, is the process of transforming raw data into a desired form, often using techniques like dimensionality reduction.
Feature Engineering vs. Hyperparameter Tuning
Feature engineering involves leveraging domain knowledge to create features that enable machine learning algorithms to perform better. Hyperparameter tuning refers to selecting the optimal set of hyperparameters for a learning algorithm to improve model performance. Feature reduction is an example of feature engineering applied to data.
Features: Characteristics that describe the problem or data. Also called attributes.
Parameters: Variables that the machine learning algorithm tries to tune to build an accurate model.
Why Dremio Users Should Know About Feature Engineering?
As a data engineering and analytics platform, Dremio provides users with the ability to perform advanced data transformations and manipulations, making it an ideal tool for feature engineering tasks. Dremio's powerful data preparation capabilities, including the ability to work with various data formats, manipulate complex data structures, and apply transformations at scale, can greatly streamline the feature engineering process.
By integrating feature engineering into their data analysis workflows with Dremio, users can effectively improve the performance and accuracy of their machine learning models, leading to more accurate predictions and better business outcomes.
