  We present predictions for soft-drop event shapes of hadronic final states in
electron-positron annihilation at next-to-next-to-leading order accuracy in
perturbation theory obtained using the CoLoRFulNNLO subtraction method. We
study the impact of the soft drop on the convergence of the perturbative
expansion for the distributions of three event shape variables, the soft-drop
thrust, the hemisphere jet and narrow jet invariant masses. We find that
grooming generally improves perturbative convergence for these event shapes.
This better perturbative stability, in conjunction with a reduced sensitivity
to non-perturbative hadronization corrections makes soft-drop event shapes
promising observables for the precise determination of the strong coupling at
lepton colliders.
