Mass Valuation/Appraisal is used in many jurisdictions as the statutory basis for assessing land or capital values for the determination of local authority rates and other land and property taxes which may apply. The valuation methods vary substantially between jurisdictions although the underlying aim ñ to estimate values as at a specified date as consistently (but not necessarily as accurately) as possible ñ is reasonably universal. Given the wider interest is questions of valuation accuracy, what levels of consistency and accuracy should be expected from these mass valuation processes? Are existing international guidelines adequate? This paper will examine some quality assurance aspects of the mass valuation process and their political implications. It will particularly focus on mass appraisal in New South Wales, Australia where there has recently been an investigation by the NSW State Ombudsman into the Mass Valuation Process (October, 2005). Land taxes are not liked and their financial impact is not necessarily fair and equitable. The political reality is that issues and concerns over land taxes are, in part, transformed into criticism of the valuations on which they are based. Many of the issues associated with mass appraisal in a statutory context are universal - they apply in virtually all jusisdiictions. Recent experience from Australia will be of interest and may be of assistance in addressing these problems elsewhere.