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Predictive Analysis

We use the data set described above and the list of tasks given in Table 1 in order to measure compactness and the number of clicks required to complete a task. Screen snapshots for Excel and InfoZoom displaying the population census data are given in Figures 4 and 5 respectively.

Figure 4. A typical Excel spreadsheet

Figure 5. InfoZoom in "Zoomed Out" mode

The compactness measurements are summarized in Table 2. The computation is based on counting the number of rows and columns displayed per unit area. We use the default font and display settings for Excel and InfoZoom and we do not use any special features for hiding columns or rows from the display. We also resize the column width in all three tools so that they have the same display semantics (i.e. text strings in all row and column entries including the headers appear in their entirety).

Table 2: Compactness Measurements
 HiDTV Excel InfoZoom 0.16 col. per in2 0.09 col. per in2 0.1 col. per in2 0.41 row per in2 0.26 row per in2 0.24 row per in2

We observe from Table 2 that both Excel and InfoZoom have approximately the same row and column compactness. Note that this result corresponds to a "zoomed out" mode in InfoZoom where all column headers are legible. HiDTV is slightly more compact where twice as many rows and columns fit within the same display area.

The number of clicks required to perform a task is given in Table 3 for all three interfaces.

Table 3: Number of Mouse Clicks per Task
 Task HiDTV Excel InfoZoom 1 4 7 7 2 5 7 7 3 5 7 7 4 13 12 12 5 8 10 10

We adjust the display size for all three interfaces so that to view the full table we would require 5 horizontal and 2 vertical scrolls. In HiDTV no horizontal scrolling is required unless the number of columns selected exceeds the display size. The calculations given in Table 3 depend on the item position in the row and column. For example, New York is located in the eleventh row so that no scroll down is required. Our calculations are based on worst case assumptions.

Next: Analysis of HiDTV Up: COMPARATIVE EVALUATION Previous: Task Scenarios