This article discusses the testing process, data conversion plans, changeover methods, and investigation techniques for analysis design and modeling. It covers unit testing, integration testing, and system testing, as well as options for changeover methods such as parallel changeover, direct changeover, phased changeover, or pilot changeover. The article also recommends involving employees and IT professionals in the post-implementation evaluation process and using investigation techniques like observation, interviews, questionnaires, sampling, and examination.