In fluid mechanics the turbulent flows are omnipresent. In many instances a central turbulent stream is surrounded by fluid in non-turbulent state (e.g. jets, wakes, plumes). Those two regions are separated by a sharp and highly convoluted interface layer named turbulent/non-turbulent interface (TNTI). The contorted nature of the TNTI poses practical difficulties in analysing the flow dynamics in its proximity. The intermittent sweeping of fixed points near the TNTI by the turbulent stream complicates analysis. To overcome this problem conditional statistics have been developed since the work of Bisset et al. In conditional statistics the TNTI is taken as the reference surface over which statistics can be reexpressed as a function of its distance. Conditional statics are nowadays widely employed as enable the unambiguous separation of turbulent and irrotational fluid and preserve flow features that would be otherwise masked. However several different methods have been introduced. In the most common procedures many local reference axes are constructed onto the TNTI points aligned normally to the TNTI. Afterwards the axes used to collect data as a function of the distance from the interface. Variants of this methodology differ mainly for the calculation of the normal (2D or 3D) and for the interface representation (whole interface or envelope simplification). In this work we explore a less common approach based on the calculation of minimal distance form the TNTI. This enables the unambiguous definition of distance from the TNTI avoiding possible spurious attributions that can occur using the local reference axes. Comparing the results obtained using the local reference axes with the minimal distance we show how the different metrics impact the physical description of key quantities near the TNTI, such as enstrophy and dissipation.