Abstract
Some users of conversational systems sometimes complain of difficulties of understanding the operational sequences. The reason of the difficulties seems to be attributed that the users can not proceed through “plan-do-see” cycles smooth, because some failures of their system interface design exist and thus the system models are unclear. In order to evaluate the user interface conditions which enable their users to proceed with “PDS” cycles smooth, this study proposes Plan-Do-See (PDS) Analysis which can be used to evaluate system specifications or trial manufactures, without conducting actual user tests. The proposed PDS Analysis is tested to evaluate the usability of a personal facsimile, before conducting its user test. The difficulties of its operation obtained by the user test were almost forcasted by PDS Analysis, however, several usability problems related to user's mental models of operational sequence could not be forcasted. PDS Analysis is, therefore, effective in evaluating usability but is of limits for some kinds of usability problems.
