Results

The findings were classified according with their severity. Severity of a usability issue is a combination of two main factors [5]:

• The frequency the issue occurs. How rare or common is that?
• The impact if it occurs. How easy will it be for users to overcome?

To define the frequency of the problem, they were categorized per task and related to users feedback [7].

Issues x Users x Task Matrix (original)

The most frequently issues were:

• figure the summary screen information out by clicking on blocks trying to access their content

• find the current location and add waypoints to create a mission plan

• start, follow and check the status of compass calibration

• start the autonomous flight

To define the impact the issue had on the user, the tasks were classified through 5 levels [6]:

Level 1: Prevents Task Completion

Level 2: Creates significant delay and frustration

Level 3: Problems have a minor effect on usability

Level 4: Subtle and possible enhancements/suggestions

Level 5: Bug

Usability problems classified as level 1 and 2 can have a devastating effect on the popularity of a product, even if they are "objectively" quite easy to overcome dependending on their persistence their market impact could be huge once the user experience is frustrating. [5]