Revenue from the rendering of services is recognised when the outcome of the transaction can be estimated reliably, by reference to the stage of completion of the transaction at the balance sheet date, using requirements similar to those for construction contracts. The outcome of a transaction can be estimated reliably when: the amount of revenue can be measured reliably; it is probable that economic benefits will flow to the entity; the stage of completion can be measured reliably; and the costs incurred and costs to complete can be reliably measured.