This document discusses various methods for collecting data in statistics for the built environment, including experiments, interviews, questionnaires, and observation. It provides details on 5 main methods: experiments, face-to-face interviews, telephone interviews, questionnaire surveys, and mail/postal questionnaires. For each method, it outlines the advantages and disadvantages in terms of costs, response rates, accuracy of data, and potential for interviewer bias. The goal is to help researchers determine the most effective approach for obtaining required data at minimum cost.