Simple Random Sampling: Techniques, Pros, and Cons

What is Simple Random Sampling?

Simple random sampling is a type of probability sampling technique involving randomly selecting elements from a population. 

This method is often used in research studies to ensure that the data collected is representative of the entire population. It is considered one of the most basic forms of sampling and the most efficient way to select a sample from a population.

4 Different Simple Random Sampling Techniques

There are several methods to implement simple random sampling effectively. Here are the main techniques.

1. Lottery Method

This is a traditional sampling method. In this, each member of the population is assigned a unique number. All numbers are placed in a container (like a box or hat), and numbers are drawn randomly without looking.

For example, suppose you have 100 employees and want to select 10. Then, you would write numbers 1 to 100 on slips of paper, mix them, and draw 10 slips.

2. Random Number Generator

This simple random sampling technique uses software to generate numbers. These are the numbers that's assigned to the members of your population.

For example, suppose you want to select 50 students from a total of 500. The software will generate 50 unique numbers between 1 and 500. The students corresponding to those numbers would be your sample.

3. Random Number Tables

In this method, researchers can use pre-printed tables that contain random numbers. Each number corresponds to a member of the population.

For instance, if you have a list of participants numbered from 1 to N, you can look up random numbers in the table and select participants based on those numbers.

4. Anonymized Selection

This is similar to the lottery method. Same, Same, but different - if you know what we mean. In this technique, instead of using numbers, names are written on slips of paper and drawn randomly.

Consider a classroom setting, for example. You might write each student's name on a slip of paper and draw names to form a sample group.

How to Do Simple Random Sampling | 8 Simple Steps

Here is a step-by-step guide on how you can conduct simple random sampling. 

Step 1 - Choose a Sampling Frame

The sampling frame is the list of everyone in the population you want to study. You have to decide who or what you want to include in your study. For example, if you are studying students, your population might be all the students in a school.

Following up, you have to create a list of all members of this population. This could be a roster of students, a list of customers, or any other relevant group. Also, make sure the list is current and includes everyone you want to sample.

Step 2 - Choose a Sampling Method

Now, decide how you will randomly select people from your sampling frame. 

The easiest way is to use a random number generator (RNG), which can be found online or in statistical software. For smaller groups, you can write names on slips of paper and draw them from a hat.

Step 3 - Draw Random Numbers

This step involves generating numbers that will help you select participants. If you have a printed table, pick numbers at random from it until you have enough for your sample size. If using software, enter the range of numbers that correspond to your sampling frame and let it generate random numbers for you.

Step 4 - Select Participants

Now it's time to choose your sample based on the random numbers generated. Look at your random numbers and find the corresponding names or items in your list.

Always make sure that each selected number corresponds to a different participant so that everyone has an equal chance of being chosen.

Step 5 - Collect Data from Participants

After selecting your participants, gather the information you need. There are many ways to collect data, but the fastest, easiest, and cheapest one is through surveys. While creating the surveys, make sure to curate the questions. Keep it short, to the point, and formal.

Nowadays, everything is AI, and so are surveys. SurveySparrow offers an AI-powered survey builder. Just add in your prompt and the tool will do the rest. Here's a sneak peek into how the feature will work.

The feature is available in the free version of the tool. So, feel free to try it out.

Step 6 - Analyze the Data

Once you have collected all your data, it's time to look at what it tells you.

Depending on what you are studying, use basic statistics (like averages) or more complex methods if needed. Also, make sure your sample reflects the larger population by comparing key characteristics (like age, gender, etc.).

Step 7 - Select the First Element on the List

Identify which participant will be sampled first based on your random selection process. Go through your list and find out which participant corresponds to the first random number you generated.

Step 8 - Repeat Until All Desired Elements Are Selected

Continue selecting participants until you reach the number you need for your study.

Use your RNG or number table again for each selection to maintain randomness. And don't forget to document! Write down how you selected each participant for transparency and future reference.

Pros and Cons of Simple Random Sampling

The following are some major pros and cons of simple random sampling.

Pros of Simple Random Sampling

1. Fair Selection

Everyone in the population has an equal chance to be chosen. This helps to avoid bias and ensures that the sample represents the whole group.

2. Easy to Use

The sampling method is simple and straightforward. Anyone can understand and apply it without needing special skills or knowledge.

3. Reduces Bias

Because the selection is random, there’s less chance for sampling bias. Researchers can’t influence who gets picked, which leads to more trustworthy results.

4. Simple Data Analysis

Analyzing data from simple random samples is easier because the statistical methods used are not complicated.

5. Flexible for Different Sizes

This method works well for both small and large groups, making it a good choice for various types of research.

Cons of Simple Random Sampling

1. Hard to List Everyone

It can be tough to get a complete list of everyone in the population, especially if it’s large or spread out. Missing people can lead to an unbalanced sample.

2. Not Very Flexible

Once you start selecting your sample, it’s hard to change things if new information comes up about the population.

3. Needs Larger Samples

To get reliable results, you often need a larger sample size, which can take more time and money to manage.

4. Risk of Sampling Errors

Sometimes, by chance, the selected sample might not accurately represent the population. For example, you might accidentally pick mostly one type of person.

5. Not Great for Diverse Groups

If the population is very different (like having many different age groups or backgrounds), simple random sampling might miss important subgroups. In such cases, other methods like stratified sampling might work better.

Related Read: Types of sampling methods you can use.

When to Use Simple Random Sampling?

Simple random sampling is best used when you want every individual in your population to have an equal chance of being selected.

It's often used in research studies to ensure that the data collected is representative of the entire population. It is also used in situations where it is important to select a sample quickly, such as in market research or opinion polls.