The Statement of Work (SOW) is a document that enables offeror’s to clearly understand the government’s needs for the work to be done in developing or producing the goods or services to be delivered by a contractor. It defines (either directly or by reference to other documents) all work (non-specification) performance requirements for a contractor. It also facilitates the preparation of a proposal and aids the Government in conduct of the source selection and contract administration after award. A Performance Work Statement (PWS) is a SOW for performance-based acquisitions that clearly describes the performance objectives and standards that are expected of the contractor.
The preparation of an effective SOW requires both an understanding of the goods or services that are needed to satisfy a particular requirement and an ability to define what is required in specific, performance-based, quantitative terms. The SOW should reference qualitative and quantitative design and performance requirements contained in specifications developed according to MIL-STD-961. 
Checklist: Statement of Work (SOW) Checklist
A well-written SOW has the following attributes: 
- Specifies requirements clearly to permit the government and offeror’s to estimate the probable cost and the offeror to determine the levels of expertise, manpower, and other resources needed to accomplish the task.
- States the specific duties of the contractor in such a way that the contractor knows what is required and can complete all tasks to the satisfaction of the contract administration office.
- Written so specifically that there is no question of whether the contractor is obligated to perform specific tasks.
- References only the absolute minimum applicable specifications and standards needed. Selectively invokes documents only to the extent required to satisfy the existing requirements.
- Separates general information from direction so that background information and suggested procedures are clearly distinguishable from contractor responsibilities.
- Avoids directing how tasks are to be performed and states only what results are required.
Statement of Work Format:
- Scope: This Section includes a brief statement of what the SOW should cover. The scope paragraph defines the breadth and limitations of the work to be done.
- Applicable Documents: Military handbooks, government instructions, service regulations, technical orders, and policy letters, as a type, are not written in language suitable for contract application.
- Requirements: Specific work tasks developed to satisfy program needs, are essentially the contractor work requirements.
- General Requirements
- Technical Objectives and Goals
- Specific Requirements
A Work Breakdown Structure (WBS) should be used in developing the SOW. A WBS provides the framework for a disciplined approach of structuring and defining the total project or program. When preparing the SOW a complete application of a WBS may not be necessary in all programs, however, the underlying philosophy and structured approach can and should be applied. The Contract Line Item Number (CLIN) and the SOW should be constructed to correlate with the WBS. Use of a WBS during SOW development facilitates a logical arrangement of the SOW elements and provides a convenient check-list to trace all necessary elements of the program and ensure that they are addressed in the SOW. 
The SOWs should be consistent with the proposed appropriation to be charged from a Purpose-Time-Amount standpoint. Specifically, the funds being cited on the SOW should be used for the proper purpose, within the legal timeframes established by Congress, and within the amounts authorized, appropriated and allocated to the program.
Whether the SOW is written by the government or the contractor (or some combination of both), it is a key element of a contract. After contract award, requirements of the SOW (and associated specifications) constitute the standard and discipline for the contractor’s effort. It comprises the baseline against which progress and subsequent contractual changes are measured. Both the Government and the contractor look to the SOW as a key document defining the responsibilities of both parties. The SOW is shown in its entirety in Request for Proposal (RFP) Section C of the uniform contract format, or incorporated by reference then listed in and attached to Section J.
- See MIL-HDBK-245D Appendix B: Work Words/Product Words, for important key words.
- See Software Examples for SOW
AcqLinks and References:
-  MIL-HDBK-245D “DoD Handbook for Preparation of Statement of Work” – 3 April 1996
- MIL-STD-961E “Specification Format” – 2 April 08
- Financial Management Compendium Overview Statement of Work
- Statement of Work Checklist
- A CORs Guide to Statement of Work