A Web-Based Methodology
Mauro Mosconi -- Marco Porta Dipartimento di Informatica e Sistemistica -- Università di Pavia Via Ferrata, 1 -- 27100 -- Pavia -- Italy firstname.lastname@example.org -- email@example.com
The purpose of this paper is to illustrate the methodology we developed in order to start a comparative usability study for different implementations of visual control flow constructs.
Since loops in data-flow visual languages ( Hils 1992) may be difficult to understand ( Greenand Petre 1996), we decided to test the usability of the solutions we devised for VIPERS, a data-flow visual language developed at the University of Pavia ( Mosconiand Porta. 1998). To get useful indications, we opted for a comparative analysis, also referring to the well-known data-flow language LabView ( Vose 1986), where iterative constructs are implemented according to a totally different philosophy.
Among the possible evaluation methods ( Preece 1993), we elicited observational evaluation,which involves observing or monitoring users' behavior while they are using an interface, and survey evaluation,which means seeking users' subjective opinions. To collect data about what users do when they interact with the test interface, employment of direct observationwas avoided. In fact, if users are constantly aware that their performance is being monitored, their behavior may be strongly influenced (Hawthorne effect). Instead, we used software loggingto record the dialog between user and system. In particular, our methodology is based on the use of the log filesof a web server, as will be illustrated. Moreover, we elicited questionnaire forms to support the survey evaluation.