Cumulative histograms for the deconvolved 3D velocity dispersions (left panel) and apparent sizes (right panel) of identified structures as published by Cantat-Gaudin et al. (2018; red) and Kounkel & Covey (2019; blue). Cantat-Gaudin et al. characterized members close to known clusters with relatively small velocity dispersions. Kounkel & Covey identified much larger structures, but more than 90% of the populations feature velocity dispersions greater than 5 km s⁻¹. Young structures (< 100 Myr) in the sample from Kounkel & Covey (2019; dashed blue line) also feature mostly relatively large velocity dispersions.