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Glossary

Survey glossary

The terms you'll meet when designing and analyzing surveys, in plain language.

Survey
A structured set of questions used to gather information from a group of people about their opinions, behaviors, or characteristics.
Sample
A subset of people selected from a larger population to take part in a survey, chosen to represent the whole group.
Sample size
The number of people who actually complete a survey. A larger sample size generally makes results more reliable, though with diminishing returns.
Calculate the sample size
Margin of error
A range, usually written as plus or minus a percentage (for example, ±5%), that shows how much the sample results may differ from what you would get by asking the entire population.
Calculate the margin of error
Confidence level
The probability, commonly set at 95%, that the true population value falls within the survey's margin of error if the survey were repeated many times.
Response rate
The percentage of people invited to a survey who actually complete it. A low response rate can reduce how reliable the results are.
Net Promoter Score (NPS)
A loyalty metric based on a single question: how likely someone is to recommend on a scale of 0 to 10. It is the percentage of promoters (9 and 10) minus the percentage of detractors (0 to 6), and ranges from -100 to 100.
Calculate your NPS
CSAT (customer satisfaction)
A measure of how satisfied customers are with a product, service, or interaction. It is usually asked with a rating scale and reported as the percentage of satisfied responses.
CES (customer effort score)
A measure of how much effort a customer had to make to complete a task, such as resolving an issue or making a purchase. It is usually asked with a single question on an easy to difficult scale.
Likert scale
A rating scale, typically with five or seven points ranging from "strongly disagree" to "strongly agree", used to measure attitudes or opinions.
Open-ended question
A question that lets people answer in their own words instead of choosing from preset options. It provides rich detail but is harder to analyze.
Non-response bias
A distortion that occurs when the people who do not respond differ systematically from those who do, so the results no longer represent the whole group.