The accuracy of the balance sheet and the estimated profit of a concern depend upon the correct valuation of the assets and liabilities . the valuation of the assets is made by the proprietors or officials of company or the firm. the auditor has simply to apply certain tests regarding the valuation of the asset. he is entitled to rely upon the certificates of component person such as valuers , surveyors etc. If he does so he, must mention this fact in his report . He cannot be expected to possess the technical knowledge to find out the value of the assets. Under such conditions , he should the valuation also refer to the invoices to find out the prices at which such assets were acquired. Of course he cannot guarantee the correctness of the valuation of the assets.