Processing of passive intermodulation detection results

A PIM (passive intermodulation) diagnosis is generated for one or more wireless networks which have equipment deployed at a plurality of cell sites. Data is received representing PIM detection results from PIM detection devices at the cell sites, the detected PIM including PIM caused by passive intermodulation between carriers of the one or more wireless networks. The data representing respective PIM detection results is normalized to account for transmission power and frequency allocation of respective cell sites, and the normalized data representing respective PIM detection results is correlated with data relating to a condition of respective cell sites and/or an environment of the respective cell sites to produce correlation results. The PIM diagnosis is generated in dependence on the correlation results.