Unstructured questionnaire is a kind of questionnaire with no rigorous structure and no need to design a certain format. This is an open questionnaire. The design of this questionnaire only conforms to the research theme, and the communication between researchers and respondents is conducted through unstructured questionnaires, which are only designed in principle. So researchers and respondents can communicate freely.

Structured questionnaire is a rigorous questionnaire that needs to be designed according to a certain format. This is a closed questionnaire. The standardization of the questionnaire is very high, that is, all the questions asked by the respondents, the order and way of asking questions, and the way of recording the respondents' answers are completely unified. So researchers and respondents can't communicate freely.

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The biggest advantage of structured questionnaire is that the survey results are easy to quantify and can be used for statistical analysis. This is a statistical survey. Compared with another statistical survey-unstructured questionnaire, the biggest feature of structured interview is that it can control the reliability of survey results. Another advantage of structured questionnaire is its high recovery rate and high response rate.

Structured questionnaire has a wider scope of application, and it can freely choose the content of investigation, ask some complicated questions, and conduct in-depth investigation on certain specific issues selectively, thus greatly expanding the scope of application.

Structured questionnaires can not only answer questions, but also observe the attitudes and behaviors of the respondents, so many non-verbal information about the contents of the questionnaire can be obtained that unstructured questionnaires can not.