  The presence of short-range chemical order can be a key factor in determining
the mechanical behavior of metals, but directly and unambiguously determining
its distribution in complex concentrated alloy systems can be challenging.
Here, we directly identify and quantify chemical order in the globally single
phase BCC-TiVNbHf(Al) system using aberration corrected scanning transmission
electron microscopy (STEM) paired with spatial statistics methods. To overcome
the difficulties of short-range order (SRO) quantification with STEM when the
components of an alloy exhibit large atomic number differences and near
equiatomic ratios, 'null hypothesis' tests are used to separate experiment from
a random chemical distribution. Experiment is found to deviate from both the
case of an ideal random solid solution and a fully ordered structure with
statistical significance. We also identify local chemical order in TiVNbHf and
confirm and quantify the enhancement of SRO with the addition of Al. These
results provide insights into local chemical order in the promising TiVNbHf(Al)
refractory alloys while highlighting the utility of spatial statistics in
characterizing nanoscale SRO in compositionally complex systems.
