IT requirements are to be developed in-house or outsourced all the activities up to the production of a specification of business requirements are your responsibility as the customer. Many information systems development contracts assume it is possible to know what the requirements are at the start, and that is possible to produce a specification that unambiguously expresses the requirements. For all but the simplest systems this is rarely true. Requirements analysis is an iterative process; the system requirements will change during the period the system is being developed. It will require user involvement throughout the development process. You will also need to be aware of the implications for fixed-price contracts and change control.
System development is complex and subject to rapid change. You must consider the advantages of modular or incremental development, perhaps with more than one provider; you will be responsible for deciding on an appropriate customer/provider interface. You must also be aware of the implications of the cost of maintenance when the system is in operation. Requirements will change during the life of the system and maintenance costs can be a major component of the total cost of ownership.
Close consultation and involvement with users to ensure that their needs really will be met and that the new system will support the proposed processes
Willingness on both the customer and provider side to work collaboratively
Scrutiny of provider plans throughout the procurement process; this is essential in ensuring that objectives are delivered.
You must pay particular attention to ergonomics and human factors; if users do not like the system they will not use it. Usability criteria should be incorporated into requirements and design documentation. You must also consider special user needs, such as disabled users, circumstances of use, novice/expert users.