The differences in the participant's performance when using and not using the BGPS are striking, since the A phases demonstrate the participant's inaccurate and erratic performance using his own skills, but coming within 30.
The upward slope (poorer performance) between Trials 3 and 4 in both A phases indicates that the intervention with the BGPS was begun following a drop in performance, which meets the requirement of the experimental design.
Since lower-level data points--that is fewer errors--indicate high performance, it is obvious that using the BGPS is superior for this skilled individual.
The data demonstrate that the novice users in Experiment 1 were capable of locating the 25-foot chalk circle with minimal BGPS-geotracking training and that the experienced user in Experiment 2 was able to pass within 1 foot of the target in every trial using the BGPS and geotracking technique.
In addition, since only one of the three commercial GPS brands was tested, older versions of the BGPS software were used, and larger groups of participants would yield more data and likely lead to further instructional methods.
A single-subject design with A-B-BCB-BC interventions was used, in which A = baseline or no BGPS, B = BGPS with no electronic waypoint marker at the target house, and BC = BGPS plus an electronic waypoint marker at the target house.
These differences in levels indicate increasing efficiency in using the BGPS standard functions (B) over no BGPS (A) and greater efficiency using BGPS with electronic way-points (BC) over the use of standard functions (B).
With the exception of the participant with low vision (P3) in the orientation test of Experiment 1, the data in both studies demonstrate the marked improvement in wayfinding performance when the participants used BGPS than when they used only O&M skills.
One established her place in a mental map of the area with BGPS and moved quickly to the target; another used BGPS to follow a route more or less to the target; and the third forsook her functional vision and did not read house numbers and instead followed the BGPS instructions to the target.
Although the participant knew the area well, he traveled to the targets more efficiently with BGPS than by using just his knowledge and skills.
The results clearly show that BGPS was advantageous to the participants.