Typically achieved sample sizes
New Zealand and Australia: Ideally surveys achieve a minimum sample of n=400 nationally representative respondents.
United States: For the US, surveys achieve a minimum sample of n=800 to allow for detailed analysis of smaller subgroups, such as by state.
Why does sample size matter?
Population size and accuracy: The size of the population does not impact the accuracy of survey estimates—only the sample size affects accuracy.
Margin of error:
A typical sample of n=400 provides a margin of error of 4.6%.
Doubling the sample size to n=800 reduces the margin of error only slightly, to 3.5%.
Explore statistical significance: Click here to learn more.
Filtering for targeted insights
If you want to survey a specific subset of the population (e.g., 18–34-year-olds), you can:
Use profiling questions to filter your audience.
Expand the sample size of your test.
How can sample sizes be expanded?
While building your survey, simply select ‘Expanded sample’ in the Audience block of the Brief page.
This allows you to increase your sample size by running your survey over two (or more) nights:
Costs:
If the incidence rate is 50% or greater, the second survey run costs the same in credits as the first survey run.
If the incidence rate is between 20%–49%, the second survey run is free. No extra credits required.
If the incidence rate is less than 20%, we recommend that you update your targeting to ensure that a robust sample size can be achieved.
Need help? Contact [email protected] for more information.
Custom panel integration
Your own customer base: Survey up to 1,000 respondents using Ideally’s Custom Panel integration.
Learn More: Reach out to our team to explore this option further.
Key takeaways
Accurate sampling: Larger sample sizes improve accuracy, but gains diminish as the size increases (e.g., n=400 to n=800).
Targeting options: Filtering and boosting provide flexibility for specific audience insights.
Expert guidance: Consult our team to determine the ideal sample size for your project.