Early Lifecycle Work: Influence of Individual Characteristics, Methodological Constraints, and Interface Constraints

Abstract

Thispaper reports the results of an experiment undertaken for theCADPRO (Constraints And the Decision PROject) project. Subjectswith varied experience produced data flow diagrams (DFDs) usinga DFD tool generated by CASEMaker, a meta-CASE tool. Half thesubjects received routine notice of instances of internal (asopposed to hierarchical) methodological constraint violationsvia an unobtrusive window whilst the other half did not. TheDFD tool automatically recorded subjects' delivery and constraintprofiles. Video records, observer notes, and subject debriefingswere also used to yield other performance data. While evidencewas found in support of the research model underpinning the CADPROproject, the model needs to be revised to take into account theaffects of human-computer interface constraints and the differentspeeds with which people work. We learnt an important lessonabout subject randomisation, which is not to assume that allsubjects can be treated alike if they share the minimum necessaryexperience thought required of the problem. We believe it isimportant for every subject-based experiment to consider andunderstand the performance of individuals. Because of the complexityof constraint environments in CASE tools we also conclude thatstudies comparing extreme programming approaches with conventionalCASE tool approaches are needed to help determine if the struggleto understand the constraint environment at a high level of abstractionis worthwhile or not. Further experiments, possibly replicationvariants of this one, are needed to help validate our interpretations.