What Exactly is It, What is It for, and Where Does the Data Come from to Create One?
Project schedules have different levels of detail. For example, activities in a preliminary schedule are typically longer in duration than those in a baseline schedule, and activities in a short-interval schedule are typically broken down at a granular level. The short interval schedule is a planning tool and a progress tracking tool. From my experience, the schedule is created to reflect the previous week’s work completed, and the three weeks of planned work. On a daily basis, superintendents and field engineers who are in charge of running the field operations meet and collaboratively work together to update and rework the plan if there are changes to it. The data required to create a short interval schedule comes from the CPM schedule, usually the monthly progress schedule, and the detailed work plan. You may have heard about “Pull Planning”, which might sound like a new concept to some people, but the truth is that it is about a short interval schedule – bringing all the parties together to plan the project at a lower level of detail.
Designing and Maintaining an Effective Short Interval Schedule, Aka Three-Week Look-Ahead Schedule
Situation:
Ineffective design and use of a short interval schedule result in unreliable schedule updates.
In most cases, the main CPM schedule is not detailed enough to show the day-to-day tasks at a granular level, and this is where the short interval schedule comes in to cover some of the missing details. Even though the short interval schedule may break the work into finer detail, the important thing is to align the short interval schedule to the activities in the main CPM schedule. It is wasteful to have multiple schedules on the same project that are not aligned. The short interval schedule is the most accurate schedule on the project if it is designed and managed based on set criteria.
Problem Statement:
The challenge is ensuring that the short interval schedule has relevant and accurate information to plan and manage the project and update the CPM schedule.
Best Practice:
Design and develop the short interval schedule from the main schedule using consistent activity grouping names. In other words, the main schedule should serve as the basis for creating the short interval schedule and the work plans. By utilizing an identification number, there should be a fundamental correlation between activities in the main schedule and the representative activities/tasks in the short interval schedule. For reference purposes, all other activities/tasks that do not correlate with the main schedule must be supported by an issue/change tracking number.
Activities in the short interval schedule should be aligned to the cost account codes in the Foreman’s daily time card for each period.
The short interval schedule is the most accurate, as it captures day-to-day activities and issues as they occur. In addition, the daily field report from the superintendents should be used to augment, validate, and close the loop on critical information missing from the short interval schedule.
The graphics should be such that delays should be easily depicted. For example, a delay happens between activities or occurs after an activity is started. Suppose a new and approved work item was added in the field, which delays the original work items. In that case, the applicable graphics should be used to show what activity was delayed.
A short interval schedule should clearly indicate if an activity is ongoing or complete; that way, users can differentiate an ongoing activity from one that is complete. Another option would be to add a %complete column next to the dates. This approach is preferred, as it provides the necessary data required to update the CPM activities on percent complete.
Case in Point:
Two of the most reliable documents for updating the CPM schedule are the daily field report and the short interval schedule. The accuracy of these two documents is based on the fact that they capture project events contemporaneously as they occur; as such, there is no room for memory loss, selective memory, and inaccurate reporting. However, without aligning and structuring the short interval schedule to align with the CPM schedule, the chances are that some level of guesstimation will happen, meaning that the CPM schedule will be incorrectly progressed. For example, one of the critical aspects of a quality schedule is the ability to trace and verify data used in the schedule. The short interval schedule presents the most accurate forecast and representation of the current project condition. Failure to properly structure this tool by synchronizing the activities/tasks with the activities in the CMP schedule would result in a flawed account of how a project was constructed.
