Theory of Constraints Handbook - James Cox Iii [22]
Neimat (2005) provides a detailed analysis of IT project failure research from the Standish Group by annual IT surveys of 18,000 executives showing the trends in failure rates from 1994 (over 80 percent of projects were challenged or failed) through 2000 (about 70 percent of projects were stressed or failed); a summary of several more recent research efforts examining IT project failures and a description of the Federal Bureau of Investigation (FBI) Virtual Case File project failure. His listing of causes of project failure is similar to the listings across the 40-year period: poor planning, unclear goals and objectives, objectives changing during the project (scope creep), unrealistic time or resource estimates, lack of executive support and user involvement, failure to communicate and act as a team, and inappropriate skills. Interestingly, the descriptions of the failure and success variables listed in the various articles across this 40-year time period are quite similar.
Single Project Management Literature
PERT/CPM is criticized for failing to provide achievable completion dates, for consistently underestimating budgets, and for using resources inefficiently (e.g., Klingel, 1966; Badiru, 1993; Meredith and Mantel, 2003, 134–135, 649–652). These failures might be traceable to a faulty initial plan or to an inadequate control process. A variety of methods for both planning and controlling projects has been espoused by researchers (Wiest and Levy, 1977; Badiru, 1993; Kerzner, 1994; Meredith and Mantel, 2003), yet no consensus on either modifications to or a replacement for the traditional PERT/CPM planning and control technique have resulted.
As most research has been conducted in the single project environment, most critiques of PERT/CPM have also been focused on the single project environment. Kerzner (1994) states that PERT: (1) is end-item oriented—it separates the planners from the doers; (2) assumes infinite capacity; and (3) fails to recognize the lack of history on which to base estimates. Other researchers have found similar problems and have criticized certain PERT/CPM characteristics. Wiest and Levy (1977) question (1) whether activities themselves and their durations (and associated distributions) and precedent relationships can be known in advance; (2) the lack of cyclical and conditional activities; and (3) the assumption of an inverse linear relationship between cost and duration (activity crashing). Van Slyke (1963) and later Schonberger (1981) found that activity variability causes project duration to exceed PERT estimates, that is, as activity duration variability increases so does the difference between planned and actual project duration. Both found that PERT assumes path independence and questioned whether variance on one path might cause another path to be “late.” Van Slyke further identified the cause as interdependence of activities on the “independent” paths. Whether explicitly stated or simply suggested by the focus of their research, many researchers ultimately question the PERT/CPM assumption of infinite capacity and PERT/CPM’s disregard of activity duration variability.
Multiple Project Management Literature
Not unlike other business environments, the management of multiple projects has certain problems that must be recognized prior to the development of new tools for planning and control. Recent research in the area of multiple project planning and control has recognized several shortcomings of the PERT/CPM method. Researchers have explored resource assignment rules to better plan multiple projects (e.g., Lee et al., 1978; Trypia, 1980; Kurtulus and Davis, 1982; Kurtulus, 1985; Kurtulus and Narula, 1985; Allam, 1988; Mohanty and Siddiq, 1989; Bock and Patterson, 1990; Deckro et al., 1991; Dean et al., 1992; Abdel-Hamid, 1993; Kim and Leachman, 1993; Lawrence and Morton, 1993; Speranza and Vercellis, 1993; Yang and Sum, 1993; Vercellis, 1994; Tsai and Chiu, 1996) and have investigated the issue of multiple project control on both an organizational basis (e.g., Coulter, 1990;