Ok, so far the analysis on the map interaction shows that there is no huge difference in the way the users interact with the map. LSI seems to spread the results all over the available space. On the contrary, CNG returns rankings which are much wider than LSI, with the resulting effect of pushing the points of the map on the top part of the quadrant.

The interesting fact which emerges is that CNG offers the relevant points much closer to the query origin, in the central lower part of the map. The subsequent analysis of the items selected shows exactly this point: while LSI mixes the most relevant items in the jungle of the other results, CNG keeps them much closer to the query origin in a space that is less populated by other results (see the map below).

So, where to go next? Two ideas so far: (a) Mapping the final selected points to see whether they are more dispersed with CNG or LSI; (b) Trace the interaction trails to assess if there are common patterns of exploration of the points in the map.

Apart from this extra analysis on the map then I am more concerned with the numerical results from the experiment. Our goal is always to check whether there is a difference between CNG and LSI in the user experience. Is there any outscore of one of the two methods concerning: (1) relevant results selected; (2) time needed to select the relevant results; (3) user perception of appropriateness; (4) number of query composed; (5) average time spent for each query; … 

Tags: information metric, information retrieval, information visualization, interaction design, map algorithms, maps, data mining