Methods and apparatus are disclosed for analyzing network performance of a network comprising a plurality of network nodes. The method may comprise: obtaining a plurality of probe measurements in respect of a target node, the probe measurements resulting from probe test-messages being sent via different network paths to said target node and relating to a network performance characteristic in respect of the paths taken by the respective probe test-messages and probe response-messages associated therewith and being dependent also on local processing of the respective probe test-messages at said target node; determining respective measures of unexpectedness in respect of the probe measurements; comparing said respective measures of unexpectedness and in dependence on the comparison, assigning a weighting in respect of said target node; and determining a network performance analysis measure in dependence on at least one probe measurement and on the weighting.