Capitalisation of rental income: use actual rents for market value unless specific factors justify projected rental changes. Valuation by income capitalisation should use the actual existing rental where it compares favourably with similar properties; a valuer's substitution of a substantially lower hypothetical rent and application of a fixed yield to reduce market value is unsupported by accepted valuation authority. Departures from actual rent require specific, documented factors indicating future change, since expected variability is reflected in the yield rate not by arbitrarily lowering current income.