Evaluation results focusing on usability and user experience are often difficult to be taken into account during an iterative design process. This is due to the fact that evaluation exploits concrete artefacts (prototype or system) while design and development are based on more abstract descriptions such as task models or software models. As concrete data cannot be represented, evaluation results are just discarded. This paper addresses the problem of discrepancy between abstract view of task models and concrete data produced in evaluations by first, describing the requirements for a task modelling notation: (a) representation of data for each individual participant, (b) representation of aggregated data for one evaluation as well as (c) several evaluations and (d) the need to visualize multi-dimensional data from the evaluation as well as the interactive system gathered during runtime. Second: by showing how the requirements were integrated in a task modelling tool. Using an example from an experimental evaluation possible usages of the tool are demonstrated.