Questionnaire recovery rate equals questionnaire recovery rate/divided by questionnaire distribution. The method of defining the value of questionnaire recovery is: the questionnaire recovery rate is equal to the recovered questionnaire divided by the distributed questionnaire, and the effective recovery rate is equal to the recovered valid questionnaire/distributed questionnaire = (recovered questionnaire-invalid questionnaire)/distributed questionnaire. The questionnaire recovery rate is the ratio of questionnaires that respondents can answer and are recovered by researchers after the questionnaire is issued.