Hackamack, Lawrence C. (Lawrence Carroll), 1921-||Novak, Ralph S.
M.S. (Master of Science)
Department of Management
Critical path analysis
Program Evaluatloa and Review Technique (PERT) and Critical Bath Method (CPM) are two widely used planning and scheduling methods. The procedure for their use utilizes a network diagram showing the inter-relationship of the many individual tasks which must be performed before the end point of the program can he reached. In order that schedule planning can occur, these Individual tasks must be assigned time estimates at as early point in the project - often when little is known about the specific details of the work being estimated. In the manufacturing portion of the estimating activities which produce the information later used in the overall PERT and CFM networks, "representative" data is often used. Representative data are the records of the methods used end the times required to produce fabricated parts for an earlier project. They are used as a basis for estimating for current projects when there is enough similarity between the two to warrant such use. For the typos of projects for which PERT and GPM are useful, however, at least one complicating factor affects the use of "representative" data. This complicating factor is the ever-changing makeup of the machine tool inventory. Where this occurs frequently, "representative" data which is based on one set of machines quickly become useless for estimating when those machines have been replaced with others. The problem than becomes one of updating this now inapplicable "representative" data to the point where it will, once again, be appropriate for estimating. Additionally, this updating should be simple and quick of accomplishment. The present study has proposed that this problem might be satisfactorily solved by some application of Productivity Criteria Quotients. Productivity Criteria Quotients, or PCQ, is a measure of the changes in machine tool productivity capabilities as a result of changes in the design of these tools. The PCQ for a particular type of machine, an engine lathe for example, is a whole number which is a function of the year of manufacture only, regardless of the particular manufacturer or the model's thus eliminating the minute detail involved in evaluating individual machines, feature by feature, the Productivity Criteria Quotient concept was considered to be an estimating tool incorporating a degree of approximation matching that inherent in the PERF and CPM procedures, themselves. A method for converting representative data has been proposed which will require a minimum of time and effort by estimating personnel. This method calls for the conversion of the basic PCQ numbers into "multipliers" which reflect the percentage increase or decrease in productivity capability between machines of any pair of years of manufacture. This multiplier, when applied to the time estimate for an operation on the original machine, will account for idle difference in productivity capability from the original machine to the current machine and will, yield a valid current time estimate. The conclusion of the study is that the procedural method proposed by the study is valid if the correlation between productivity changes indicated by Productivity Criteria Quotients and actual productivity changes is, itself, valid. This latter, correlative validity has not been established by the study. Proof of a valid correlation must be provided by further studies, some of which are presently in progress.
Haspelmath, Charles E., "The application of productivity criteria quotients to schedule determinations using PERT and critical path method" (1965). Graduate Research Theses & Dissertations. 5313.
ix, 64 pages
Northern Illinois University
Rights Statement 2