When we talk about machine learning, we often compare 2 important processes: machine learning inference vs prediction. This debate is all about how algorithms help us understand and predict outcomes using data. While they may seem similar, inference and prediction actually have different purposes and are used in different ways.
This article will focus on understanding the 7 major differences between inference and prediction. We will also share practical examples to show how you can apply these concepts in different real-life scenarios.
Understanding Machine Learning Inference vs Prediction
Machine Learning refers to the study of algorithms and statistical models that allow computer systems to perform specific tasks effectively without being explicitly programmed. It involves developing methods that enable machines to learn from data and make decisions or predictions based on patterns and meaningful insights derived from that data.
Prediction and inference represent 2 ways machine learning models use data to generate new and useful information. Let’s discuss both of them in detail.
What Is Machine Learning Prediction?
Prediction, in machine learning, is the process of using a trained machine learning model to estimate the output for new, unseen data points. Once it is trained on a representative dataset, the model predicts based on fresh, previously unseen data instances.
The goal of prediction is to utilize existing patterns and relationships in the machine learning training data to make accurate estimates or forecasts about unseen data instances or new data points.
This could involve predicting a continuous value, like the price of a house or the future stock price, or classifying an instance into a specific category, like identifying whether an email is spam or not.
Accurate predictions are crucial for various applications, including recommendation systems, fraud detection, image recognition, and many other domains. For instance, in finance, a predictive model can be developed to forecast stock prices.
The goal here is to provide accurate forecasts rather than understanding the specific factors influencing price fluctuations at any given moment.
What Is Machine Learning Inference?
Causal inference, or simply inference refers to the process of making conclusions or drawing insights from the available data. It involves analyzing the data to uncover the underlying patterns, relationships, and dependencies between the input features and the target output variable.
Inference is used to conclude the data's underlying distribution or the dependence of the dependent variable on the model's input parameters. By studying the data and the relationships it exhibits, machine learning algorithms estimate the parameters of the chosen model or the probability distributions that best describe the data.
This understanding of the data's structure and characteristics is essential for building accurate and effective machine-learning models.
For example, if you want to predict the likelihood of a disease based on various patient characteristics, the inference would allow you to determine which factors (e.g., age, lifestyle, genetic predispositions) are significant predictors and how they interact to affect the likelihood of the disease.
Inference becomes particularly powerful when you want to understand cause-effect relationships. Here's how:
Through inference, you can identify which features in your data have the strongest influence on the target variable. This helps you understand what truly drives the outcome you are interested in.
Some models, like linear regression, are inherently interpretable. They reveal the mathematical relationship between features and the target variable. This allows you to see how changes in one feature cause changes in the other.
There are advanced ML techniques specifically designed for causal inference. These techniques go beyond simply observing correlations and aim to establish true cause-and-effect relationships. This can be crucial in fields like medicine or economics where understanding causality is essential.
7 Key Differences Between Machine Learning Inference vs Prediction
While both prediction and inference are important in machine learning, they have different purposes, use different methodologies, and give outcomes for different objectives.
To understand this better, let’s discuss 7 major differences between machine learning inference and prediction.
1. Purpose & Focus
Inference aims to understand the underlying relationships and structure within the data. It uncovers patterns, dependencies, and causal mechanisms that govern the data's behavior. The focus is on gaining insights into the data-generating process and the factors influencing the observed outcomes.
Prediction, on the other hand, helps forecast future outcomes based on historical data. It is similar to a weather forecast that uses past weather patterns to accurately predict future weather conditions without necessarily understanding the atmospheric science behind those patterns.
The primary objective is the reliability of these forecasts in new or unseen data situations and focuses on the model's ability to 'see into the future.'
2. Approach & Methodology
In inference, the methodology is based on statistical rigor. Analysts deploy models to estimate relationships within the data and test hypotheses about how the system behaves. This process is very thorough and involves the construction of confidence intervals and p-values to validate these estimates.
Prediction uses computational power and data to forecast outcomes. The methodology here is highly dynamic and uses complex algorithms that can process vast datasets to predict future states. Techniques vary widely, from a generalized linear model, like linear regression or logistic regression, to deep learning.
3. Evaluation Metrics
Inference is evaluated through statistical significance. It employs tests that measure the reliability of the model's estimates. These metrics are crucial for distinguishing between genuine patterns and random noise to ensure the inferred relationships are grounded in reality.
Prediction uses a suite of metrics like accuracy, precision, recall, and the area under the ROC curve. These metrics provide a multifaceted view of a model's predictive ability, assessing not just its correctness but its utility in practical applications.
4. Application Domains
Inference is needed when understanding the 'why' is as crucial as the 'what.' Fields like epidemiology, where understanding the cause of disease spread is vital, and social sciences, where investigating and explaining the dynamics of societal interactions are important, rely heavily on inference.
Prediction, on the other hand, is used in domains like finance, marketing, recommendation systems, and predictive maintenance. Here, the primary objective is to forecast future outcomes or make informed decisions based on new data.
5. Data Requirements
Inference can work with smaller and highly curated datasets. The focus is on the quality of data and its suitability for testing specific hypotheses. This approach allows for a deep understanding of the data structure and its implications.
Prediction thrives on large datasets. This is because large datasets are beneficial for training accurate predictive models, particularly in domains with complex patterns or high-dimensional data.
6. Model Complexity
Inference models prioritize simplicity for clarity. The models are straightforward so that the researchers can easily interpret the effects of different input variables on the outcome and facilitate a clear understanding of the data structure.
On the other hand, prediction models can afford to embrace complexity if it enhances predictive accuracy. Advanced algorithms and numerous parameters can obscure the model's workings but they enable it to capture and forecast complex patterns.
7. Outcome Interpretation
The results of inference are interpreted in the context of the data and its underlying processes. The inferred relationships and patterns are used to gain insights, test hypotheses, and inform decision makers how everything is related.
Prediction outcomes are more directly applicable to real-world scenarios. The predicted values or classifications are used to make decisions, forecast future events, or take actions based on the model's output.
Key Difference | Machine Learning Inference | Machine Learning Prediction |
Purpose & Focus | Understand underlying relationships and structure within the data. | Forecast future outcomes based on historical data. |
Approach & Methodology | Statistical rigor, testing hypotheses about how the system behaves. | Computational power, using complex algorithms to process vast datasets. |
Evaluation Metrics | Statistical significance, reliability of model's estimates. | Accuracy, precision, recall, area under ROC curve. |
Application Domains | Fields like epidemiology, social sciences. | Finance, marketing, recommendation systems, predictive maintenance. |
Data Requirements | Can work with smaller, highly curated datasets. | Thrives on large datasets for training accurate predictive models. |
Model Complexity | Prioritizes simplicity for clarity. | Can embrace complexity if it enhances predictive accuracy. |
Outcome Interpretation | Interpreted in the context of data and its underlying processes. | Directly applicable to real-world scenarios, used to make decisions or take actions. |
Machine Learning Inference Vs. Prediction: 4 Practical Examples
Let’s discuss 4 real-world scenarios to understand when and how to apply each technique effectively.
A. Healthcare Diagnosis
Scenario
A healthcare system analyzes patient data to detect the presence of a specific disease. This includes:
Demographic information (age, gender, location)
Medical history
Vital signs (temperature, blood pressure, heart rate)
Laboratory test results (blood work, imaging scans)
Reported symptoms
Application
Inference is primarily used here to understand the relationship between these various independent variables and the likelihood of a disease. Machine learning models are trained on historical patient data, including all the aforementioned input features and known diagnoses.
Through inference, these models can identify patterns and correlations between combinations of factors and the presence of a particular disease.
For instance, a model can infer that a combination of specific symptoms (e.g., persistent cough, fever, chest pain), lab test results (e.g., elevated white blood cell count, abnormal chest X-ray), and demographic information (e.g., age, gender) increases the likelihood of a patient having lung cancer.
This knowledge can help healthcare professionals in making more accurate diagnoses and providing appropriate treatment plans.
B. Stock Market Trends
Scenario
An investment firm uses historical stock data to forecast market trends for the next quarter. This data includes:
Stock prices
Trading volumes
Company financials (revenue, earnings, debt levels)
Economic indicators (GDP, unemployment rates, interest rates)
News sentiment
Application
Prediction is needed to forecast future stock prices or market movements based on past trends, helping investors make informed decisions. Machine learning models are trained on this comprehensive historical data.
These models identify patterns and trends in the data, which are then used to predict future stock prices or market indices. Predictive models can help investment firms make decisions about buying, selling, or holding specific stocks. This potentially increases their returns and manages risk more effectively.
C. Customer Retention Strategy
Scenario
A telecom company reviews customer data to identify factors causing customer churn. This data includes:
Service usage patterns (data consumption, call logs)
Billing history (payment records, plan changes)
Customer support interactions (call transcripts, chat logs)
Account changes (upgrades, downgrades, cancellations)
Application
Inference helps in understanding the key factors that influence customer satisfaction and retention. Machine learning models are trained on this customer data and include various aspects of their experience with the telecom company.
Through inference, these models can identify the underlying reasons behind customer churn, like poor network quality, billing issues, lack of competitive pricing, or inadequate customer support.
By inferring the relationships between various factors and customer churn, telecom companies can develop targeted retention strategies and improve their customer experience.