Final answer:
The percentage of people who complete a questionnaire out of those contacted is known as the response rate, which is crucial for survey representativeness and for avoiding selection bias.
Step-by-step explanation:
The term for the percentage of people contacted who complete a questionnaire is known as the response rate. This figure is significant in survey research and is used to gauge the quality of the survey results. A higher response rate generally indicates that the survey results may be more representative of the population. Selection bias can occur if the sample is not representative of the population, such as when using landlines to contact participants in an era where many people use cell phones exclusively. To ensure the validity of a survey's findings, it is important to consider the response rate and the potential for biases, such as selection bias or inaccurate response due to incomplete mailing lists.