Project Schedule Quality Assessment Methods

A project schedule typically models the execution plan of a contractor performing a scope of work for an owner over a specified period. The schedule’s ability to forecast task completion dates and interface requirements with other parties is a key purpose from a management perspective. Additionally, individual task execution delay or late delivery of interface requirements should be reflected in the schedule updates once activity delays have been incorporated into the schedule. It is the completion date forecasting and delay monitoring capability of a properly prepared project schedule that makes it such a valuable tool, allowing management insight into the effect of delays.

Schedule quality refers to the structural integrity of the schedule or the level at which best practices are incorporated. Schedule quality analysis, then, is the process of evaluating a schedule to ensure it is well-constructed, reliable, and adheres to best practices. Schedule quality remains one of the most pressing challenges in commercial construction.

To effectively review a project schedule, the electronic file must be made available to the reviewer. Without access to the native software file, it is difficult to review and identify potential schedule problems. Therefore, it is important when performing a schedule quality analysis to look for deficiencies in the areas of work scope, activity durations, and activity sequencing. First, the project schedule should be reviewed to ensure that the complete scope of work is represented in the schedule. Next, schedule metrics should be calculated and compared to industry norms. Then, the schedule logic should be reviewed in detail to ensure that the logic is reasonable and complete. Lastly, the project schedule’s critical path should be identified and reviewed in detail.

Schedule Quality Analysis Process

Establishing a Baseline Schedule

The first step is establishing a baseline schedule. The comparison of a completed or in-progress schedule to an earlier progress update or baseline schedule will reveal changes made to the schedule. This review can identify changes that have been made to the current schedule. These changes can then be catalogued and examined as to how they affected the schedule, the forecast of task or milestone completion date, or the required date of interface with a third party.

Scope of Work Review

To effectively evaluate a project schedule to determine if it accurately reflects the project Scope of Work, the reviewer must understand the project scope. The project contractual Scope of Work is usually identified in project documents such as the project contract, drawings, and specifications. Large complex projects are generally divided up into areas or units. The schedule reviewer should be familiar with the industry sector for the project to ensure a complete work scope review.

To review the project schedule scope of work, the project schedule activities can be exported from the schedule to a database or spreadsheet. Individual schedule activities generally have a multitude of data or activity codes associated with the activity. The activity description, along with the activity codes should be reviewed and each schedule activity can then be categorized against the work breakdown list.

Schedule Metrics Analysis

Schedule metrics can be compiled and calculated from a review of the individual schedule activities and activity characteristics. The process for this type of analysis starts with the export of all activities and activity data to a database or spreadsheet. A table of activity characteristics is created where one record or row in the spreadsheet contains all relevant information about an individual schedule activity. This table can then be reviewed and analyzed to generate various schedule metrics.

Key Schedule Metrics

Proper evaluation of project schedule metrics requires knowing what type of schedule activities are being reviewed, compiled, and tabulated. Schedules generally have a mix of Task activities, Start and Finish Milestones, and Hammock activities. Various schedule metrics calculations are made on groups of activities depending on the status of the individual activity. Whether or not that activity is complete, in-progress, or not-started can determine if the activity is included in the calculation of a particular metric.

Here are some important schedule metrics to consider:

Total Activity Count: This metric sums the total number of Task, Milestone, and Hammock activities.
Activities per Cost: This metric is a calculation of the total number of Task activities in the schedule divided by the project cost in millions of dollars.
Activity Density: Analysis of this metric involves totaling the number of task activities in progress during each month of the project, based on actual and early activity dates.
Average Activity Remaining Duration: The average activity remaining duration metric excludes completed work.
Long Duration Activities: The activity table should be reviewed for activities with excessively long planned durations.
Calendar Usage: The schedule calendar definitions are reviewed and then the activity table is evaluated to identify which calendar is applicable to each activity.
Activity Codes: The activity table is reviewed for information relating to the activity codes. The activity codes are used to organize and sort the individual activities in the schedule.
Constraints: The activity table should be reviewed for information relating to activity date and float constraints that can affect the forecasting ability of the schedule.
Average Activity Float Duration: The average activity float duration metric excludes completed work.
Float Ratio: The float ratio is simply the average activity float divided by average activity remaining duration.
Resource Loading: The project schedule is reviewed to determine whether activities have been resource loaded.
Planned vs. Actual Duration: This metric reviews completed task activities. A review of the planned duration compared to the actual duration of individual activities reveals activities that were delayed in completion.
Percent Complete vs. Remaining Duration: This metric reviews in-progress task activities. The percent complete versus remaining duration check is used to identify activities that may show incorrect progress reporting.

Schedule Logic Review

The first step in a schedule logic review is to export the activity relationships to a database or spreadsheet. The table of activity relationships should include the predecessor and successor Activity ID, activity description, type of logic relationship, and lag value. In addition to these minimum requirements, activity information from the activity table can be correlated by using the Activity ID as a common element. Information relating to activity status and activity codes indicating the project phase or area can be applied to both the predecessor and the successor activities. The schedule logic review should utilize information from both the activity data table and the activity logic table to assess the reasonableness and completeness of the schedule logic.

Key Aspects of Schedule Logic Review

Missing Logic: Each activity is reviewed to identify if it has at least one predecessor and one successor.
Milestone Logic: This metric involves the review of logic ties for milestones as well as task activities.
Excessive Lag Values: The activity logic table should be reviewed and activities with large lag values identified.
Excessive Float Values: The activity table should be reviewed for activities with excessively large float values.
Progress Reporting Errata: The activity table should be reviewed to determine if any activities have progress reporting errata.

Critical Path Analysis

The schedule reviewer should review the reasonableness and completeness of the critical path for the engineering, procurement, construction, and pre-commissioning activities, and any available near critical path activity chains. The critical path can be influenced by preferential logic, work activity estimated durations, and calculation methods used by the CPM software. The reviewer should determine if there is any evidence that preferential logic was utilized to force the critical path.

The schedule reviewer should evaluate near-critical paths and identify activities that are likely to impact contractual milestones and the project completion date, but have not been identified as being on the critical path. These identified activities should be placed on a watch list for evaluation on future schedule updates.

DCMA 14-Point Assessment

The GAO Schedule Assessment Guide develops the scheduling concepts introduced in the Cost Estimating and Assessment Guide and presents them as ten best practices associated with developing and maintaining a reliable, high-quality schedule. The DCMA's 14-point assessment provides measurable criteria for regular analysis during project schedule monitoring. These 14 metrics serve as advisory guidelines rather than rigid rules.

While the DCMA’s 14-point check is an excellent baseline, it’s merely the tip of the iceberg. Projects vary based on numerous factors, from budget and scale to geography and climate. So, I’d suggest every organization dedicate some time to understanding the nuances of each risk. Look at the frequency of each metric and the impact each has on different types of builds. To achieve this, you can add or remove certain items from their 14-point check to align schedule quality analyses with your organizational goals.

Here is a breakdown of the DCMA 14-point assessment:

Logic: Evaluates the percentage of incomplete tasks lacking predecessors or successors. Ideally, unfinished activities missing these connections do not exceed 5% of total project tasks. Every task should have at least one finish-to-start predecessor, one start-to-start predecessor, and one finish-to-start or finish-to-finish successor.
Leads: An optimal scenario is zero leads, as leads themselves can impede critical path analysis.
Lags: Lags represent the percentage of activities with positive lag, showing the delay between a predecessor's finish and a successor's start. While more flexible than leads, lags should not exceed 5% of the schedule.
Finish-to-Start Relationship: DCMA recommends that 90% of scheduled activities follow a finish-to-start (FS) relationship type, providing the clearest representation of scheduled activities.
Hard Constraints: DCMA advises limiting hard constraints to 5% of all constraints used.
High Float: Examines the percentage of unfinished tasks, with total float exceeding 44 working days. Total float should not surpass 5% of total, incomplete tasks.
Negative Float: Negative float can signal potential delays in project or milestone completion.
Long Duration Activities: If more than 5% of incomplete tasks surpass the duration threshold of 44 working days, it's advisable to break them into more minor, more manageable activities.
Invalid Dates: Analyzes forecast and actual dates of project activities to eliminate any instances of invalid dates, such as forecast dates in the past or actual dates in the future.
Resource Loading: While resource-loaded schedules are recommended, DCMA acknowledges that some schedules may not include resources.
Missed Tasks: This metric helps gauge schedule performance against the baseline plan.
Critical Path Test: This test assesses schedule logic integrity by artificially extending a critical activity's duration and observing the impact on the project completion date.
CPLI (Critical Path Length Index): Measures the efficiency required to complete a milestone on time. A value of 1.00 indicates on-track performance.
BEI (Baseline Execution Index): Evaluates schedule performance relative to the baseline plan, focusing on team productivity. Like CPLI, a value of 1.00 indicates on-target performance.

DCMA 14-Point Assessment

Project Controls and Schedule Quality

Project Controls allow project management and schedulers to systematically and accurately measure project performance throughout the whole project by putting metrics and checkpoints in place to ensure intended progress and performance levels are being met. However, schedule quality analysis is just a fraction of project controls - but a critical part of ensuring data integrity. After conducting the analysis, you can use your schedule data to support project controls by identifying and responding to impacts, delays, and inefficiencies of ongoing work.

Missing logic is a key driver of schedule quality because every activity (except the first and last) should have a predecessor and successor. This ensures the continuity of work. Constraints and deadlines can significantly impact your schedule’s flexibility and critical path. In doing so, various schedule metrics can be compared across every update.

The Importance of Continuous Assessment

Schedule quality analysis is not a one-and-done exercise. It should be assessed at every schedule update and tracked throughout the project lifecycle. The Schedule Quality Report gives the details behind each Schedule Quality Grade. Achieving a high-quality schedule is just the first step. Then, you have to maintain that quality and use the data to support the control of your project outcomes.

Important Note: a high-quality schedule does not equal a healthy project.

How to Perform a Project Schedule Risk Assessment