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Starting Simple: The Strategic Advantage of Baseline Models in Machine Learning
by Andrey KustarevMay 1st, 2024
Too Long; Didn't Read
Starting your machine learning projects by introducing a simple baseline model is not just a preliminary step. It is a strategy. A strategy that aligns with Agile methodologies promoting efficiency, effectiveness, and adaptability. It helps to establish benchmarks, maximize value while minimizing waste, provides a simple explanation of the logic behind the model, and allows incremental testing and validation.
Starting a new machine learning project brings a rush of enthusiasm, and it might be quite tempting to jump straight into the deep end. There are plenty of the latest cutting-edge models or complex algorithms that you might have read about. They promise groundbreaking results, and avoiding the temptation to experiment with them right off the bat is a tough task.
Any modern entrepreneur is eager to test state-of-the-art techniques and showcase sophisticated (and successful) projects to the community. Yet, this enthusiasm, while good, can sometimes take up significant time as you fine-tune hyperparameters and encounter the difficulty of implementing complex models.
In this process, there is one main question that needs to be asked: How do we actually measure the effectiveness of our model?
Finding out whether the complexity of our model is justified or if the performance is genuinely superior can be challenging. This happens when there is no simpler point of reference. Here, having a baseline model becomes very important. A baseline gives that essential reference point — it is straightforward, quick to build, and inherently explainable. Surprisingly, often a baseline model, which may only take 10% of the total development effort, can achieve up to 90% of the desired performance, producing a highly efficient path to reasonable results.
The idea of starting simple is not just an easy approach for beginners — it is a fundamental practice that stays relevant at all stages of a data science career. It is a grounding mechanism and a great reminder to balance our ambition for complexity with the practicalities of clear, easy-to-understand, and manageable solutions.
Understanding Baseline Models
A baseline model is the most basic version used to tackle a problem. Typically, these models include linear regression for continuous outcomes or logistic regression for categorical outcomes. For example, a linear regression can predict stock returns based on historical price data, while logistic regression can classify credit applicants as high or low risk.
This approach differs from more complex models like neural networks or ensemble methods, which, while powerful, can make grasping the problem more difficult and increase the time needed for development due to their complexity and significant computational resources.
Benefits of Starting with a Baseline Model
Benchmarking
Benchmarking is a highly important initial step in the development of any ML model. When you set up a baseline model, you establish a fundamental performance metric that all the models that come after (which are usually more complex) have to surpass to justify their complexity and resource consumption. This process is not only a great sanity check but also grounds your expectations and gives you a clear measure of progress.
For example, imagine developing a model to forecast financial market trends using a simple moving average (SMA) as the baseline. This SMA might use short-term historical data to predict future stock prices, achieving an initial accuracy of 60% in forecasting market movements correctly. This model then sets the benchmark for any advanced models that follow. If a sophisticated model, such as a Long Short-Term Memory (LSTM) network, is later developed and achieves an accuracy of 65%, the performance increment can be precisely measured against the initial 60% baseline.
This comparison is crucial for determining whether the 5% improvement in accuracy justifies the additional complexity and computational demands of the LSTM. Without a baseline like this, making informed decisions about the scalability and practical application of more complex models becomes challenging.
This approach to benchmarking makes sure that improvements to model complexity are justified and will result in real improvements, all while making the development process aligned with effective outcomes.
Cost-Effectiveness
Following a cost-effective approach in ML is key. Especially when you set out on a goal to align your processes with principles that put maximizing value while minimizing waste as a priority. When you start off with a baseline model, you reduce the resources and time needed for initial model development and testing. This means quick prototyping – and that is essential for instant feedback and iterative improvements.
With this baseline, any complexity that you add can now be carefully evaluated.
For example, if you want to make the transition to a more complex algorithm like a vector autoregression (VAR) and find that it only marginally increases forecasting accuracy, you need to rethink whether this slight improvement actually justifies the additional computational demands and complexity. The answer might be no. Then the simpler model remains the more cost-effective option.
By focusing on cost-effectiveness, you ensure that resources are used efficiently and achieve more than just technical enhancements. Also, it delivers practical, value-added solutions that are justified in terms of performance improvement and resource allocation. This way, each investment in model complexity is warranted, which contributes to the overall project goals without expenses that are out of proportion.
Transparency and Interpretability
In sectors like finance where decisions must adhere to strict regulatory standards, the transparency of models is not just a business advantage. It is a strategic approach that significantly helps in the process of meeting regulations and facilitates easier communication with stakeholders who may not have a (profound) technical background.
Let’s take our SMA model. It is easily interpretable because its outputs are directly related to the input data. This makes it easy to explain how each input influences the predicted outcome. When decisions based on the model's forecasts need to be justified to external regulators or internally to non-technical team members, this simplicity is key to your processes.
If a decision based on the SMA model's forecasts is questioned, the transparency of the model allows for a quick and simple explanation of the logic behind its work. This can help with regulatory reviews and audits and improve trust and adoption among users and decision-makers. Moreover, as model complexity increases, for instance moving to more complex algorithms like ARIMA or VAR models for more nuanced predictions, the interpretability of the initial SMA baseline becomes a benchmark for what level of explanation you need to present.
By using regressors like feature significance scores or SHAP values combined with more complex models, the progress of any further model performance stays transparent. This helps the purpose of the safety procedure to not be discarded for more advanced models. The point of the simple baseline model is to always implement the condition that the overall structure and significance will be kept even as the level of complexity increases. This ensures provisions of compliance and communications that will be effective.
Risk Management
Risk management is another important aspect of developing machine learning models, especially in sectors like finance where accurate and reliable forecasts have an impact on decision-making. Having a simple baseline model is a great strategy for managing these risks.
A straightforward baseline provides an understandable starting point, which allows you to gradually (and safely) add enhancements to model complexity.
For example, the SMA model (while basic) makes a solid foundation for finding underlying patterns and potential anomalies in stock price movements. Using it helps identify early signs of volatility or abnormal market behavior. Doing that is crucial, avoiding significant financial risks before deploying more complex predictive algorithms.
Moreover, using a baseline model minimizes the risk of overfitting. It’s a common pitfall in financial modeling. Overfitting happens when a model is too finely tuned to historical data and captures noise rather than the underlying pattern. Because of this, you can get misleading predictions and get unreliable trading strategies as a result. A simpler model with fewer parameters is less prone to this issue, ensuring that the predictions it offers are generally applicable to unseen data.
Increasing complexity as SMA advances on the small moving average model like ARIMA and VAR become more complex, SMA's simple structure can help us systematically consider the effectiveness of each added complexity. This stepwise improvement in complexity helps maintain control over the model’s performance, making sure that each additional complexity layer provides a clear benefit and does not bring in unwarranted risk.
This systematic approach to escalating model complexity helps in understanding how changes to the model affect its behavior and reliability. It also ensures that the risks are always well-managed. When you start with a simple baseline and carefully control each stage of development, you ensure that the forecasting models remain both powerful and safe, supporting financial decision-making.
Key Considerations When Implementing Baseline Models
To select the most suitable baseline model, you need to understand the business problem and data characteristics. For example, time-series predictions for financial markets might start with an ARIMA model as a baseline to capture temporal dynamics in a simple way. Data quality and preprocessing also play key roles; even the simplest model can perform poorly if fed inadequate or poorly preprocessed data.
And lastly, knowing when to transition from a baseline to a more complex model is essential. This decision should be guided by incremental testing and validation, in line with Agile's iterative approach.
To Sum Up
Starting your machine learning projects by introducing a simple baseline model is not just a preliminary step. It is a strategy. A strategy that aligns with Agile methodologies promoting efficiency, effectiveness, and adaptability. Approaching your project in this way can significantly enhance project outcomes by ensuring that every increase in complexity is justified and adds tangible value. Embracing simplicity is a powerful thing. It is an especially great strategy in fields like finance where decisions must be swift.
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