The notion that reasoning develops in distinct phases of thinking as individuals progress from simplistic learning of facts to predicting integrated relationships was explored as subjects considered housing issues. Suggestions for developing and instructing housing programs are presented. Subjects included 13 students and faculty members at three levels of learning: (1) novice beginners, consisting of undergraduates; (2) intermediates, who were baccalaureate holders and graduate students in housing programs; and (3) experts (faculty members and professors in the university housing department). Data were collected using a demographic questionnaire, an achievement test, a semistructured interview, and a problem-solving activity. A systematic progression of reasoning about housing issues was evident in these subjects, and it is suggested that individuals and families experiencing housing selection problems might show a similar progression of reasoning with experience. Implications for home economics education are discussed. This phases-of-reasoning instructional prototype provides insight for the design of housing instruction that makes reasoning explicit from a problem-solving perspective. Appendix A illustrates the cognitive processes of the three groups of subjects. Appendix B lists housing concepts expressed within the groups. Two tables and one figure illustrate the discussion. A 27-item list of references is included. (SLD)