Explanation:

Contract costing is used to records the cost of big contracts. If the contracts are completed in the financial year itself, profit will be transferred to profit & loss account. To find out the profitability , value of work certified and work uncertified need to be recorded.

Work certified is the work completed and certified by the engineer and work uncertified is that which is completed but not certified by the engineer. Work certified and work uncertified are part of work in progress and to be recorded in contract account.