Some other advantages of this model, according to Clay (1993), are that it provides a systematicway of looking at many different aspects of the curriculumdevelopment process. This modelseems to appeal to educational leaders because it emphasizes the importance of producingevaluative data for decision making. To service the needs of decision makers, the Stufflebeammodel provides a means for generating data relating to four stages of program operation:context evaluation, which continuously assesses needs and problems in the context to helpdecision makers determine goals and objectives; input evaluation, which assesses alternativemeans for achieving those goals to help decision makers choose optimal means; processevaluation, which monitors the processes both to ensure that the means are actually beingimplemented and to make the necessary modifications; and product evaluation, whichcompares actual ends with intended ends and leads to a series of recycling decisions. Duringeach of these four stages, specific steps are taken: