Definition of Confidence Level
A confidence level is a value that indicates how many times out of 100 repetitions of the same survey the same result would be obtained. This confidence level is closely linked to the margin of error.
For example, if 1,000 respondents are randomly selected from an infinitely large population and a survey is conducted, the margin of error at an 80% confidence level is ±2.0%p. If the response rate for a specific variable in a survey result that reflects this confidence level and margin of error is 50%, then in 80 out of 100 repetitions of the same survey, the result would fall between 48% and 52%.
Changing the Confidence Level
The confidence level is not a calculated value; it is the researcher's standard for "how rigorously I want to examine the data." It can be changed based on the researcher's needs. Depending on how rigorously you want to analyze the data, the confidence level can be changed to 80%, 90%, or 95%.
📌 What confidence level is appropriate?
Social opinion surveys typically analyze results at a 95% confidence level in order to estimate the awareness and behavior of the overall population as accurately as possible. Election polls are a representative example.
General marketing research more commonly uses 80% or 90%. Observing small differences can help identify opportunities faster than competitors.
While setting a higher confidence level provides more stable results, it also increases the likelihood of obtaining results that are already obvious to everyone. Therefore, from a marketing perspective, it is generally preferable to examine even small differences at an 80% confidence level.