This question does not ask about the monetary cost of constructing a wall, fence or other physical barrier.
According a to U.S. Government Accountability Office report published in February 2017 SOUTHWEST BORDER SECURITY Additional Actions Needed to Better Assess Fencing's Contributions to Operations and Provide Guidance for Identifying Capability Gaps (GAO-17-331)
CBP cannot measure the contribution of fencing to border security operations along the southwest border because it has not developed metrics for this assessment
Specifically, we found that CBP had not accounted for the impact of its investment in border fencing and infrastructure on border security. We recommended that CBP conduct an evaluation of the impact of tactical infrastructure on effective control of the border.6 In February 2017, we found that CBP had not developed metrics that systematically used the data it collected to assess the contributions of border fencing to its mission.7
which again reiterated the need for the development of metrics which would allow assessment and measurement of
the contributions of pedestrian and vehicle fencing to border security along the southwest border
which the CBP concurred with
The agency concurred with our recommendation, and officials reported that CBP plans to finalize metrics in January 2019.
Given that it is still currently early in January 2019, has the U.S. Government yet published any metrics whereby the contribution of a wall or physical barrier can be independently assessed and measured?