*3.1. Analysis of the Reaction Time Variable*

To establish a relationship between the reaction time variable and the designed taskload of each exercise, it was decided that a combined graph should be created. The same graph shows the designed taskload profile, which is different for each of the exercises, and superimposed on it are the reaction time values for each of the six participants.

A representation of the four exercises can be seen in Figure 3. Each participant is represented by a different geometric shape and colour, as can be seen in the legend that appears under the four plots.

**Figure 3.** Combined representation of the designed taskload profile of the different exercises together with the reaction time values for the six participants. The first row of graphs presents the two simplest exercises, with Exercise 1 on the left and Exercise 2 on the right. The second row presents the data from Exercise 3 on the left and Exercise 4 on the right.

Each of the exercises has been associated with a different colour to facilitate the interpretation of the plots. The taskload profiles of Exercise 1 appear in magenta, those of Exercise 2 in green, those of Exercise 3 in orange, and finally those of Exercise 4 in purple. To correctly interpret Figure 3, the following aspects should be considered.

• The x-axis of the four graphs represents the time elapsed since the start of the simulation. All exercises lasted 45 min.


As can be seen in the figure above, the taskload distribution profile for each exercise is different. In the exercise design process, the starting point was a specific shape of designed taskload and a total reference taskload score. Specifically:


Table 1 shows a summary of the design characteristics of each of the exercises to compare their design values. The second column presents the total taskload value for each of the exercises. The next two columns present the maximum value of the designed taskload and the minute of simulation at which this value was expected to be reached.

Taking all the above into account, the obtained values for reaction time and the designed taskload for each of the exercises were represented in a combined graph.

The initial hypothesis was that reaction time would increase as the taskload faced by the ATCO increased. Given that the situation in the sector is more complex, it would be expected that the controller would take longer to assess the workload.

However, such a correlation was not observed in any of the four exercises. Contrary to what might be expected, the highest reaction time values appear at the beginning of Exercise 1. The explanation for these values is not that the situation in the sector was more complex, but that the participants were not yet familiar with the platform, the radar screen, or the additional windows.

Some isolated cases that confirm the initial hypothesis are the values of Participants 3, 5, and 6 in Exercises 1, 2, and 4, where the reaction time values increase at times with high taskload values. However, in general, the expected generalised relationship is not observed. Based on the analysis conducted, it was considered that, in the case of the registered data from participants, reaction time was not a significant variable in the study, and it was decided to discard it.
