Software Metrics SEI Curriculum Module SEI - CM - 12 - 1 . 1 December 1988

In 1972 Halstead first reported his investigation into natural laws of algorithm analogous toFerrari86laws of natural or physical sciences. The basic idea Ferrari, D. “Considerations on the Insularity of Per-is to separate the physical structure of algorithms formance Evaluation.” IEEE Trans. Software Eng.from the logical structure of algorithms. His theory SE-12, 6 (June 1986), 678-683.has been refined since that time. Furthermore, the theory has been applied to algorithms in differentAbstract: It is argued that systems performance languages and different environments. In thisevaluation, in the first 20 years of its existence, has study, Halstead’s criteria are applied to 154 PL/Ideveloped in substantial isolation from such disciprograms. This sample contains the largest algo-plines as computer architecture, system organizarithms to be measured by his methods to date. Ation, operating systems, and software engineering. subset of 120 of the programs has been measuredThe possible causes for this phenomenon, which previously by other techniques which describe theseems to be unique in the history of engineering, are basic attributes of the programs herein discussed.explored. Its positive and negative effects on computer science and technology, as well as on perfor-The correlation between observed program length,mance evaluation itself, are discussed. The draw-N, and calculated program length is investigated.backs of isolated development outweigh its advan-Of the 154 programs, 34 have been developed usingtages. Thus, instructional and research initiatives tostructured programming techniques, while the otherfoster the rapid integration of the performance eval-120 were not. Correlations between observed anduation viewpoint into the mainstream of computercalculated values of N are reported to be 0.985 (forscience and engineering are proposed.the structured programs) and 0.976, respectively.This article discusses the degree of isolation of per-formance evaluation studies from other computerElshoff78science/software engineering activities. AlthoughElshoff, J. L. “An Investigation into the Effects ofperformance evaluation is now considered a sepa-the Counting Method Used on Software Sciencerate field, the author questions whether this is desir-Measurements.” ACM SIGPLAN Notices 13, 2 (Feb.able and suggests that performance evaluation con-1978), 30-45.siderations should be introduced into computer sci-ence and engineering courses in general.Abstract: Professor Maurice Halstead of Purdue University first defined a set of properties of algo-Fitzsimmons78rithms in 1972. The properties are defined in terms of the number of unique operators, unique Fitzsimmons, A. and T. Love. “A Review and Eval-operands, total operators, and total operands used uation of Software Science.” ACM Computing Sur-to express the algorithm. Since 1972, independent veys 10, 1 (March 1978), 3-18.experiments have measured various sets of algo-Abstract: During recent years, there have beenrithms and have supported Halstead’s theories con-many attempts to define and measure the “complex-cerning these properties. Also, new properties haveity” of a computer program. Maurice Halstead hasbeen defined and experiments performed to studydeveloped a theory that gives objective measures ofthem.software complexity. Various studies and experi-This paper reports a study in which different meth-ments have shown that the theory’s predictions ofods of counting operators and operands are applied