Determination of sample size is one of the critical decisions in forming a customer survey. Though you can find numerable statistical guides, and sample size calculators available, many people find these tools to be intimidating or tough to use.
To make the sample size determination easier for you, we have come with a guide that will help you select a sample size to perform a basic survey without any need for the complex formulas.
Understand the relation of the sample size with the effect size
A survey should be conducted keeping in mind the effect that it will create on the business and its reputation among national and global buyers. The size of the sample is inversely proportional to the size of the effect. This implies that samples that are larger in size cause a smaller effect. Similarly, the smaller sample size generates large effect sizes.
Ovation MR is a popular website that provides an easy and efficient sample size calculator to calculate sample size based on population total, confidence level, and margin of error.
Step1: Choose the minimum sample size to form a customer survey
According to most of the statisticians, the minimum size of the sample is a hundred. If the population is below a hundred, then you would have to survey all of them.
Step2: Choose the maximum sample size to form a customer survey
The maximum sample size is ten percent of the total population, provided that it does not exceed beyond the thousand. This is appropriate to give a precise result. By considering population over the limit of a thousand people would not add much to the precision of the survey but takes more amounts of money and time.
Step 3: Choose a number that lies between the minimum and maximum value as per the situation
The ideal size of the sample should be between the minimum and maximum value of the survey.
You should select a size closer to the minimum sample size when:
- You have limited resources in terms of money, and time
- You only require a rough approximation of the results
- You do not have to categorize the sample size into varying groups during the analysis
- You use only a few large subgroups of men and women
- You have the notion that most of the people will provide similar answers
- The conclusion of the survey doesn’t produce significant consequences.
You should select a size closer to the maximum sample size when:
- You have adequate resources such as money, and time to perform it
- It is essential to obtain precise results.
- You need to divide the sample into various groups at the time of the analysis such as different socio-economic levels, age groups, etc.
- If you think that people will provide different answers
- The decisions that are based on the survey results are critical, costly, or can have critical repercussions.
This guide will help you calculate sample size using formulas, pragmatism, and common sense. Once you have successfully determined a sample size, you should not forget to write impactful survey questions to design an effective survey form as well as a pre-test and test your questionnaire.