Property Indices such as the ROZ/IPD Real Estate Index rely on valuations. For this valuation guidelines, that should be used by the valuers, have been developed. Recent studies on uniformity and consistency of valuations for the ROZ/IPD Real Estate Index indicated that both the guidelines and compliance with the guidelines needed improvement. It was for this reason that ROZ initiated the screening of valuation inputs and outputs to detect extraordinary data before the construction of the Index. In this paper the methods and results of the screening are presented.