A method performed by a network node or a wireless communications device for determining a reporting threshold related to proximity based positioning in a wireless communications network. For each of a plurality of candidate reporting thresholds the network node or the wireless communications device calculates a corresponding localization accuracy metric based on a deployment information related to a deployment of the wireless communications network, an evaluation position related to the evaluation of a received signal, a propagation model relating the evaluation position and the evaluation of the received signal, and the respective candidate reporting threshold. The network node or the wireless communications device then determines the reporting threshold based on the plurality of corresponding localization accuracy metrics.