How to determine the sample size of an online survey
Posted: Tue Jan 07, 2025 6:37 am
Determining the sample size for a survey has become one of the most common questions for independent market researchers. The process of determining the best sample size to gather so that you can make an informed decision is not as complicated as you might think (or remember from your statistics classes).post12Es
Since there is no magic number, there are a few things you'll want to determine before you start figuring out what your online survey sample size will be :
Your goals and objectives . What are you hoping to gain from the survey? Are you planning to project the results onto an entire population or demographic? Do you want to see how a specific group thinks? Are you trying to make a BIG decision or just set a direction? If you are going to PROJECT your survey results onto a larger population, then the sample size is crucial and you will want to make sure it is balanced and reflective of the population. If you are trying to get a sense of preferences, then it is not crucial.
How precise do you need or want to be? How PRECISE do you want the results of a survey to be in order to simulate what the actual value would be, if EVERYONE responded? Again, if the survey is going to determine how millions of dollars are going to be spent, you need to be VERY precise. The more precise you want to be, the larger the sample size you want to have, and thus the better your survey will represent the population at large. Now if your population is small, say 200, then you may require a full census instead of just a sample.
How confident or certain do you want to be in your results? Think about the word Confidence from a RISK perspective. How much risk are you willing to take? This is where the percentage in the confidence romania phone number comes into play. How confident do you want to be? 98% confident? 95% confident? Understand that the confidence percentage you choose has a HUGE impact on the number of people you will need to complete the survey and this can increase the size of the survey, the sample you need to have at the end and that means increased costs for your survey. This helps to understand the real numbers behind the percentages and the costs associated with achieving them. For example, if you want to be 99% confident it means gathering an additional 1000 respondents. This in turn means paying for the sample or keeping your survey running an extra week, you will need to ask yourself if you are willing to make that trade-off for a more accurate result.
What kind of variability are you looking for? In other words, how similar or different is the population? If you are surveying consumers on a broad topic, then you may have a LOT of variability and you will need MORE sample. But if you are surveying a very homogeneous population, then the variability will be less and you can sample with FEWER people. So more variability equals more sample and less variability equals less sample. If you are unsure, you can start with 50% variability.
Calculate your response rate. Of course you want everyone to take your survey, but we know that's not going to happen. Your response rate will depend on how engaged your sample or population is with your product, service organization, or brand. The higher the response rate, the more engaged your list will be. Your BASE sample size is the number of responses you MUST get. To achieve those goals, you'll need to increase your list size—remind people to finish your survey, and take a look at your survey structure, too. For example, sometimes people won't take long surveys. So, if you reduce the number of questions in your survey, your response rate can increase.
Since there is no magic number, there are a few things you'll want to determine before you start figuring out what your online survey sample size will be :
Your goals and objectives . What are you hoping to gain from the survey? Are you planning to project the results onto an entire population or demographic? Do you want to see how a specific group thinks? Are you trying to make a BIG decision or just set a direction? If you are going to PROJECT your survey results onto a larger population, then the sample size is crucial and you will want to make sure it is balanced and reflective of the population. If you are trying to get a sense of preferences, then it is not crucial.
How precise do you need or want to be? How PRECISE do you want the results of a survey to be in order to simulate what the actual value would be, if EVERYONE responded? Again, if the survey is going to determine how millions of dollars are going to be spent, you need to be VERY precise. The more precise you want to be, the larger the sample size you want to have, and thus the better your survey will represent the population at large. Now if your population is small, say 200, then you may require a full census instead of just a sample.
How confident or certain do you want to be in your results? Think about the word Confidence from a RISK perspective. How much risk are you willing to take? This is where the percentage in the confidence romania phone number comes into play. How confident do you want to be? 98% confident? 95% confident? Understand that the confidence percentage you choose has a HUGE impact on the number of people you will need to complete the survey and this can increase the size of the survey, the sample you need to have at the end and that means increased costs for your survey. This helps to understand the real numbers behind the percentages and the costs associated with achieving them. For example, if you want to be 99% confident it means gathering an additional 1000 respondents. This in turn means paying for the sample or keeping your survey running an extra week, you will need to ask yourself if you are willing to make that trade-off for a more accurate result.
What kind of variability are you looking for? In other words, how similar or different is the population? If you are surveying consumers on a broad topic, then you may have a LOT of variability and you will need MORE sample. But if you are surveying a very homogeneous population, then the variability will be less and you can sample with FEWER people. So more variability equals more sample and less variability equals less sample. If you are unsure, you can start with 50% variability.
Calculate your response rate. Of course you want everyone to take your survey, but we know that's not going to happen. Your response rate will depend on how engaged your sample or population is with your product, service organization, or brand. The higher the response rate, the more engaged your list will be. Your BASE sample size is the number of responses you MUST get. To achieve those goals, you'll need to increase your list size—remind people to finish your survey, and take a look at your survey structure, too. For example, sometimes people won't take long surveys. So, if you reduce the number of questions in your survey, your response rate can increase.