May 1, 2024

What is Data Sampling and How is it Used in AI?

Imagine you wanted to know the average height of people in your city. It would take forever to measure every single person! But if you took a random sample of a few hundred people, you could calculate an average that would be pretty close to the actual average height. That's the power of data sampling.

Large population of individuals narrowed down by data sampling.

People use data sampling in fields like statistics, machine learning, scientific research, and public opinion polling. It allows researchers and analysts to:

  • Process data faster

  • Reduce computational costs

  • Use time and resources more efficiently

By focusing the analysis on a representative sample, data sampling makes it possible to work with datasets that would otherwise be too large or complex to analyze.

In the rest of this guide, we'll explore the fundamentals of data sampling, including:

  • How data sampling works

  • Different data sampling methods

  • Key use cases and applications

  • Challenges and considerations

  • Future outlook and trends

Whether you're studying data science or just curious about sampling, this guide will equip you with the key concepts you need to know. So, let's start by looking at the core mechanics behind data sampling.

How does data sampling work?

Selecting the correct sampling method ensures the sample accurately represents the larger population. The choice depends on the research objectives, data characteristics, and available resources. Here are some commonly used sampling techniques:

Simple random sampling

A straightforward approach where each data point has an equal probability of being selected. This technique minimizes bias and is suitable when the population is homogeneous. For example, a market research firm might use simple random sampling to gather customer feedback by randomly selecting respondents from their customer database.

Systematic sampling

Involves selecting data points at regular intervals from an ordered list or dataset. This technique is efficient and convenient, particularly when working with large datasets. It is commonly used in quality control processes, where manufacturers might inspect every nth product coming off the assembly line.

Stratified sampling

25 colored dots representing players are grouped by color, then a simple random sample of each group is taken.

Divides the population into non-overlapping subgroups (strata) based on shared characteristics, like age, gender, or income level. A random sample is then taken from each subgroup, ensuring the sample accurately represents the population's diversity. In the picture above, we can see basketball players grouped by their position for a more representaive sample. This technique is useful in opinion polls and market research studies, where stratified sampling based on demographics can provide more reliable results.

Cluster sampling

6 clusters of randomly colored dots, then 2 clusters are selected at random to sample.

Groups the population into clusters (e.g., households, neighborhoods, or schools), and a random sample of clusters is selected. All data points within the chosen clusters are included in the sample. This technique is practical when the population spreads over a large geographical area, such as in census data collection.

Convenience sampling

Involves selecting data points that are readily available or easily accessible. While convenient, this technique may not accurately represent the population. However, it can be useful for exploratory research or pilot studies when resources are limited.

By selecting the appropriate technique, researchers can ensure their sample is representative, reliable, and aligned with their research objectives. This enables them to draw valid conclusions and insights from the data.

Data sampling use cases: from AI to market research

Data sampling has widespread application across diverse domains. Its versatility makes it a powerful tool for extracting insights from large, complex datasets. Here are some key use cases:

Machine learning and deep learning

In artificial intelligence, data sampling is crucial in training models. By selecting representative and unbiased samples from the data, researchers can ensure that their models learn from an accurate subset of the dataset. This improves the model's performance and accuracy and also optimizes training time.

For instance, in a recent study, data scientists developed a deep learning model to automate the inspection of brake components. By employing stratified sampling, the dataset included a balanced representation of different fault types and varying conditions, such as lighting and material surfaces. They used object detection algorithms, which were trained to accurately identify defects on brakes. This approach increased the model's ability to generalize and achieved impressive results, with an accuracy rate of 95.64%!

Consumer insights and market research

Companies use data sampling techniques to gain insights into consumer trends and behaviors, allowing them to make informed decisions.

A great example is the LEGO Group’s use of sampling in their "Ready for Girls" study, done in partnership with the Geena Davis Institute. By selecting representative samples from specific groups, they got a comprehensive view of how gender stereotypes affect children's creativity. This strategic sampling provided the data needed to support their global campaign, which aimed to break down gender barriers in play and creativity.

Scientific research and public health

Scientific studies commonly use data sampling. In cities like Ottawa, Canada, this practice is critical for public health for things like in monitoring water quality. According to the 2023 data from Ontario's Drinking Water System,* Ottawa conducts detailed sampling of its water sources. Tests are done for various contaminants like E. coli across raw, treated, and distributed water. 2023’s results showed that the city’s water treatment processes are highly effective, with treated water being completely free of E. coli.

These use cases show the versatility and power of data sampling across industries. By using appropriate sampling techniques, organizations can make informed decisions, optimize processes, and drive innovation.

Challenges and considerations

While data sampling offers a powerful approach to working with large datasets, it comes with several significant challenges and ethical considerations that need to be carefully addressed.

Determining the Optimal Sample Size

Line graph showing that sampling error decreases as sample representativity increases.

One of the primary challenges in data sampling is determining the appropriate sample size. The sample needs to be large enough to capture the full diversity of the dataset, ensuring the insights are reliable and representative of the entire population. However, an excessively large sample size can waste time and resources without significantly better results.

For example, consider a scenario where you are analyzing customer feedback for a large retail chain. If the sample size is too small, you might miss important trends or patterns among certain demographics or geographic regions. Conversely, if the sample size is unnecessarily large, you will spend more time and effort than necessary to reach the same conclusions.

Incomplete or biased data

Another critical challenge in data sampling is the presence of incomplete, inconsistent, or biased data. When artificial intelligence (AI) systems are trained on limited or biased data, their ability to generalize and perform effectively in real-world scenarios reduces substantially.

Bias in healthcare

For instance, health models trained primarily on data from certain demographics may provide inaccurate predictions for patients from other backgrounds. This is because the training data does not fully capture the diversity and complexity of the real-world population.

In a landmark study published in "Science", researchers found that a widely used algorithm for identifying patients' health risks exhibited significant racial bias. This algorithm predicted health care costs rather than illness, and unequal access to care meant that less money was spent caring for Black patients compared to White patients. Despite health care cost seeming to be a good proxy for health, large racial biases arose due to the choice of this flawed assumption.*

Bias in hiring

Another example of data sampling issues is famously highlighted by Amazon's AI recruiting tool, which exhibited bias against female candidates due to the historical hiring patterns reflected in the training data.*

Evolving best practices

As AI systems and data sampling techniques evolve, it's important to address these challenges responsibly. This involves refining sample size calculations, recognizing and correcting data biases, and ensuring data completeness. Developing best practices for data sampling and AI training will help mitigate risks of bias and enhance fairness in applications like healthcare and recruitment. Collaborative efforts among domain experts, data scientists, and ethicists are essential to build transparent, accountable systems aligned with ethical standards.

Future outlook

As AI and analytics continue to advance, data sampling is poised to play an even bigger role in improving business efficiency and workforce productivity. Let's explore some of the key trends on the horizon and what they could mean for you and your organization.

New frontiers in data sampling

Cutting-edge techniques like predictive sampling and adaptive sampling are starting to see wider adoption. What makes these approaches so powerful? They don't just help organizations anticipate future outcomes - they also enable quick pivots in response to evolving circumstances. Take predictive sampling: by utilizing AI and machine learning algorithms, it builds models of future trends based on past data, arming decision-makers with sharper foresight *.

Fueling the AI revolution

Building reliable AI systems requires efficiently analyzing massive datasets. That's where data sampling comes in. As sampling techniques grow more sophisticated, they're accelerating the development of AI that boosts productivity. But rather than job replacement, experts predict AI will primarily reshape and redefine roles *.

Adapting to the new normal

To stay ahead of the curve, individuals and organizations need to keep a pulse on these rapid advancements in data sampling. Embracing change means understanding what new sampling methods are capable of and getting ready for how they'll impact business strategy and the nature of work.

Data sampling and AI are undoubtedly shaping the future of work. For businesses to navigate the transition smoothly, they'll need to evolve their approaches while ensuring their people are prepared to tackle new ways of working fueled by data-driven insights.

Getting started with data sampling

So there you have it - a comprehensive look at why data sampling matters and how it's used across industries to streamline data analysis. Pretty cool, right?

But here's the thing: the world of data is always evolving, and if you want to stay ahead of the curve, continuous learning is key. That's where Dataquest comes in.


Our courses on data sampling are designed to fast-track your skills and have you applying these techniques like a pro in no time. Intrigued? You can check out our Statistics Fundamentals course to learn more about all the data sampling techniques we discussed in this article and more.

So what are you waiting for? Jump in, get your hands dirty, and start sampling some data!

Anna Strahl

About the author

Anna Strahl

A former math teacher of 8 years, Anna always had a passion for learning and exploring new things. On weekends, you'll often find her performing improv or playing chess.