Participants were asked to fill in part I of the survey before using the system. There were 5 questions. This part is used for gathering their background information to check if they are sufferers and to know more on their level of suffering for facilitating adjustments of the treatment including setting an appropriate starting level for them. After answering the question, participants were invited to take an experiment for evaluating the effectiveness of the system.

At the beginning of the experiment, reaction of the participants will be tested with a cockroach of size 3, which is the size of cockroaches that are common found in household environment. If a participant is too scared of it, cockroaches of size 2 or below will be used. After the participants have adapted to the therapy, three to four cockroaches will be added. The experiment will progress to level 2 if no refusal is received. Participants will then be asked to let the cockroaches climb over their hand or to block their road. If they succeed in doing so, cockroaches of larger sizes will be added to the environment and they will be requested to repeat the above task on the larger ones. After overcoming level 2, the experiment will get to level 3. Participant will be asked to give stimuli to the virtual cockroaches such as moving their hand over them or put their hand beside them. They have to overcome the panicky cockroaches in order to complete the experiment.

The experiment normally starts at level 1, but level 2 or 3 might be chosen as the starting level for non-sufferers or for sufferers with slight symptoms. The experiment might go back to a previous level under requests from participants.

Besides moving speed and reactions carried out by the cockroaches, size was reported as another factor affecting participants' avoidance. Almost all of the participants thought the cockroaches of size 3 or lower (less than 5cm in length) were acceptable and were able to have interactions with them. When cockroaches of size 4 or 5 (length about 6cm to 8cm) are added, 35% participants said they felt fear and appeared unwilling to interact with those virtual cockroaches. Later at their first time interactions, a hand withdrawal was observed in more than half of the cases. After one to two minutes on average, most of them succeeded at their second or third time. The following shows the agreed percentages about the system effectiveness:

From the statistics above, it might be strange to see that the percentage of non-sufferers agreeing the system helped in reducing their level of fear and finding cockroaches less scary than before is higher than that reported from suffers and others. According to the observation on participant's reactions during experiment, all of the non-sufferers actually were happy and thought it was fun to interact with the virtual cockroaches though they might be scared by them once or twice. They probably found the virtual cockroaches more interesting than the real ones which caused the above result. However, the overall percentages in those aspects were not high. The main reason due to the low percentages was the projector was too dim and its resolution was not high enough causing the images to be blurred and making the cockroaches unreal. Other reasons included they have known that the cockroaches were fakes and the stimuli given by 2D images were not strong enough to cause fear. The projector used was a 3M MPro150 with brightness 15lm. If it is replaced by a projector with higher brightness, a better result might be attained.