Constructing an IMS
The overall size of the IMS depends on many factors, including the complexity of the program and its technical, organizational, and external risks. In addition, the intended use of the schedule in part dictates its size. That is, a schedule with many short-duration activities may make the schedule unusable for other purposes such as strategic management or risk analysis. The schedule should not be so detailed as to interfere with its use. However, the more complex a program is, the more complex the IMS may become.
Generally speaking, the level of detail in the schedule should reflect the level of information available on the portion of the work that is planned to be accomplished. Both the government and the contractor must define the effort required to complete the program in a way that fully details the entire scope and planned flow of the work. In this manner, the IMS is defined to the level necessary for executing daily work and regularly updating the program. Schedules that are defined at too high a level may disguise risk that is inherent in lower-level activities. In contrast, too much detail in a schedule will make it difficult to manage progress and may convolute the calculation of critical paths.
The IMS ideally takes the form of a single schedule file that includes all activities. However, it may also be a set of separate schedules, perhaps representing the work of separate contractors and government offices, networked together through external links. Regardless of how this is achieved, the IMS schedules must be consistent horizontally and vertically. Horizontal and vertical integration forms the basis of Best Practice 5.
The IMS includes the summary, intermediate, and all detailed schedules. At the highest level, a summary schedule should provide a strategic view of summary activities and milestones necessary to start and complete a program. Decision makers use summary schedules to view overall progress toward key milestones. Summary schedules are roll-ups of lower-level intermediate and detail schedules. The dates of these milestones are automatically calculated through the established network logic between planned activities.
An intermediate schedule includes all information displayed in the summary schedule, as well as key program activities and milestones that show important steps toward high-level milestones. Intermediate schedules may or may not include detailed work activities. For instance, an intermediate schedule may show the interim milestone accomplishments necessary before a major milestone decision or summarized activities related to a specific trade or resource group. A properly defined IMS can facilitate tracking key program milestones such as major program decision points or deliverables. The important program milestones can be summarized along with the specific required activities leading up to the milestone event.
A detailed schedule, the lowest level of schedule, lays out the logically sequenced near-term effort to achieve program milestones. While each successively lower level of schedule shows more detailed date, logic, resource, and progress information, summary, intermediate, and detailed schedules should be integrated in a way such that higher-level schedule data respond dynamically and realistically to progress (or lack of progress) at the lower levels. Delays in lower-level schedules should be immediately rolled up to intermediate and summary schedules. A summary schedule presented to senior management should not display on-time progress and on-time finish dates if the same milestones in lower-level schedules are delayed.
Ideally, the same schedule serves as the summary, intermediate, and detailed schedule by simply rolling up lower levels of effort into summary activities or higher-level WBS elements. When fully integrated, the IMS shows the effect of delayed or accelerated government activities on contractor activities, as well as the opposite. Not every team member needs to digest all the information in the entire schedule. For example, decision makers need strategic overviews, whereas specialist contractors need to see the detail of their particular responsibility. Both sets of information should be available from the same data in the same schedule.
Management should take steps to ensure the accuracy of reported schedule information. In some instances, the government program management office and its contractors might use different scheduling software. However, given the same schedule data, different software products will produce different results because of variations in algorithms and functionality. Attempting to manually resolve incompatible schedules in different software can become time-consuming and expensive. If the use of different software cannot be avoided, the parties should define a process to preserve integrity between the different schedule formats and to verify and validate the converted data whenever the schedules are updated. To ensure integration, milestones need to be defined between the government and the contractor schedules. These milestones are sometimes referred to as “giver/receiver” milestones and one of their purposes is to ensure that integrated schedules reflect the same dates. Giver/receiver milestones are described in more detail in Best Practice 5.
The IMS must include planning for all activities that have to be accomplished for the entire duration of the program. A schedule of planned effort for one block, increment, or contract for a multiyear multiphased program is not a plan sufficient to reliably forecast the finish date for the program. Without such a view, a sound basis does not exist for knowing with any degree of confidence when and how the program will be completed. A comprehensive IMS reflects all activities for a program and recognizes that there can be uncertainties and unknown factors in schedule estimates because of limited data, technical difficulty, inadequate resources, or other factors in the organizational environment.
Uncertainties regarding future activities are incorporated into an IMS in part by the rolling wave process (discussed in Best Practice 3) and through schedule risk analysis (Best Practice 8). Management should verify that all subcontractor schedules are correctly integrated in the IMS with detail appropriate to their risk level. Case study 2 gives an example of high-level program dates unsupported by planned effort.
For this DOD study, we reviewed the most current schedule and cost estimates that supported DOD’s February 2012 Milestone B decision, which determined that investment in the Defense Enterprise Accounting and Management System was justified. We found that the schedule used to support the Milestone B decision included the activities to be performed by both the government and the contractor for Releases 1 through 3 of Increment 1. However, the schedule did not reflect activities to be performed for Releases 4 through 6 of Increment 1 or for Releases 1 and 2 of Increment 2. The DEAMS program manager stated that a comprehensive schedule for Increment 1 that included the activities for all six releases would not be completed until mid-2014. The program manager also stated that Increment 2 had not been included because program officials did not know the detailed activities to be performed that far in advance.
To address this issue, the DEAMS program office developed a roadmap—a planning document that briefly outlines the program’s key increments and releases and expected milestones for completion—depicting Releases 1 through 6 of Increment 1 and Releases 1 and 2 of Increment 2 with a full deployment date of fiscal year 2017. However, the program office did not provide a schedule that supported the estimated dates in the roadmap.
A schedule incorporates different levels of detail depending on the information available at any point in time. That is, near-term effort is planned in greater detail than long-term effort. Effort beyond the near term that is less well defined is represented within the schedule as long-term planning packages. Planning packages are a summarization of the work to be performed in the distant future with less specificity. By not including all work for all deliverables for both increments and all releases, the DEAMS program could incur difficulties resulting from an incomplete understanding of the plan and what constitutes a successful conclusion for the program. DEAMS program officials provided a draft of the Schedule Management Plan that documented their intent to use a planning package approach when updating the DEAMS schedule in the future.