How many survey responses do I need to be statistically valid?
In technical terms, the question of how many responses you need for your survey to be valid goes straight to the concept of survey sample size (read all about it by following that link). For now, you’re OK knowing that there’s a certain number of survey respondents you need to ensure that your survey is big enough to be reliable or ‘statistically significant.’
This one is a bit trickier. The more straightforward way to look at it is, the closer your sample is in relation to the total population, the more representative your results are likely to be. Heck, if you surveyed every single homeowner in the Twin Cities you’d be pretty certain that your results represented the views of the whole home-owning population, right? But since it’s almost impossible to survey 100% of any particular population, the next best thing is a well-designed survey where you have an acceptable level of tolerance for inaccuracy.
Let’s have a look at the table to understand this last point. You’ll notice that if you allow for greater inaccuracy–or margin of error–the recommended sample size gets smaller. If you can live with a 10% margin of error, you only need 80 out of 500 people to respond, as opposed to 220 for a 5% margin or 345 for a 3% margin.
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