Pace 54 o ——OŽANA AE vee Within the Timebox, Development Deadlines Really Work but the function: ality may slip. People in many walks of life have to meet deadlines. Writers, television producers and seminar developers, for example, must deliver material by a certain date, which means the content of the materi- al may slip. Methodologies such as RAD apply a similar constraint to the building of IS applications: There is a deadline that, is immovable, but the functionality of the system may slip. The system must work, carrying out its basic functions, but the refinements may have to be postponed in order to meet the deadline. Seventy-five percent of a system's functionality can be created relatively guickly with an automated code genera- tor, especially if reusable structures are employed. The next 15 percent may take as long to create as the first 75 percent, and the system may have to be successively re- -.. fined before the last 10 percent is com- če vole Mati dli Many of the features in the last 10 percent could be dropped or postponed for a subseguent release. Jf the refinements are added after the first version of the product has been in use, they will probably be subject to change. Adding Refinements lt is often better to add refinements after the first version has been in use because users change their minds about ; the reguired functionality of a system mad, a with it for a while. dangers of prototyping methodologies or iterative development is that the functions of a system can grow in an uncontrolled fashion. Users EEKNAPPLIGATION DEVELOPMENT APPLIED INTELLIGENCE ting a deadline practical. The Time! life cycle allows refinements to be ae until the deadline nears, at which time a working system must be delivered. Du Pont's Timebox was first used in ga: ae fibers division, which . oving to a highly automated S ufacturing environment. It was NeCeRJIE sary to create complex application soft. ware guickly, and Du Pont recognized that it is better to get a basic version of the system working, learn from the ex: perience of operating with it and then ' design an enhanced version than it is to wait for a comprehensive system at a later date. Du Pont's experience implies that: Applications Development Within a Time- struction (or SWAT) team is given a time frame within which a system must be constructed. Prior to the assigned time frame, the functions and design framework of the -. system are defined. After the time frame, the system is evaluated and a de- cision is made as to whether to put it into production. The time frame cannot be extended; however, the functionality of the system may be trimmed to complete the system within the time allotted. Within the time frame, continuous it- erative development, is done with end users and IS developers working closely together. The team is under pressure to /. 'Regulrements Planning / Buildand volve Prototype Reguest for Change : H Timebox U Wiihin the time frame, continuous iterative development is done with users and IS developers working closeliy together. The team must produce a working system by deadline. 9 The first version must be built guickly, | produce a working system by deadline. A Timebox approach, or team devel- opment in general, does not work well if "—there/is pressure to meet an impossible e. 'The setting of the deadline, or the se- lection of functions to be accomplished within an allotted time, should be the responsibility of the team or systems an- alyst working on the project. Meeting the deadline is easier if the team is fa- pi miliar with the tools and technigues, Sa aber in what they can accom- Before deciding on a realistic deadlin the SWAT team should make its own ex timation as to how long the project will take. This estimate should be made at or before the end of the final joint applica- tions design (JAD) workshop, within the RAD user design phase. By the end of the final JAD work- shop, the following should be estimated: the number of function points, inputs, outputs, logical internal files, external files and gueries, and their complexity igh, medium or low). An experienced SWAT team knows what it can achieve, It examines the JAD and uses its own guidelines for de- termining how long the project will take and whether additional assistance is needed. It may allocate a certain period of time for startup, a number of person- days for each transaction type, a period for integration testing and a period for handing over the project. SWAT teams should work on systems or subsystems that: can be completed in a short time. If the overall project is large and complex, it should be divided into subsystems, which can be built at the same time by separate teams. The SWAT team effectively signs a contract with management saying, "We will build a system of that scope by a certain date." Changing the Scope I£ the scope changes during the con- struction phase, more development time may be needed, or reguired functionali- ty must be dropped. Any change in scope should be agreed upon with man- agement-during the construction phase. Limiting functionality to meet the deadline does not mean guality must be compromised. It is essential that SWAT teams have pride in their work; no self- respecting team would put. out. work that; was less than the highest guality. The delivered system must be as bug- free as possible and must provide a set of functions that meets the user's needs when the system is put into production. Integrated CASE tools make it much easier to achieve technical guality. Functionality can vary substantially without reducing the usability of the system. Many software and electronic prod- ucts today have excessive functionality that often bewilders users. The return on development investment, goes down when unwanted or marginal functions are added. 'The Timebox development concept. places an inflexible limit on the func- tionality to be supported and the time taken to produce a working system. Next week I will discuss how innova- tive management technigues can lead to higher productivity. B The concepts embodied in RAD are de- seribed ol poe m Martin Series. For more infor- mation s volume, call ( 800) 22 1240. For information on seminars, con: tact (in the United States and Canada) Technology Transfer Institute, 741 10th St, Santa Monica, Calif. 90402 (213) 3943305. In Europe, contact Savant, 2 New St, Carnforth, Lancs, LA5 9BX United Kingdom (0524) 73% 505. nueoilo mu [S