The use of several representation techniques of algorithms, of either a textual or a graphical nature, is common in systems, which support learning of programming. The GreedEx tool, a system for interactive experimentation with greedy algorithms, incorporates some of them. This system has been evaluated several times, using subjective perception questionnaires as the main technique to gather
... [Show full abstract] data. This paper describes two empirical evaluations conducted with the aim of assessing the usefulness and/or complexity of the representation techniques supported by GreedEx. In this analysis, we combine several sources of information: subjective perception questionnaires and the metrics provided by an eye tracking device.