GAO-16-89G: the Schedule Assessment Guide

The most complete free statement of what a reliable project schedule is, and one of the few that says plainly what it will not reduce to a number.

The document

GAO-16-89G, GAO Schedule Assessment Guide: Best Practices for Project Schedules, U.S. Government Accountability Office, December 2015. 224 pages.

• Landing page: gao.gov/products/gao-16-89g
• PDF: gao.gov/assets/gao-16-89g.pdf

No successor edition could be found. The Preface states only an intention: "We intend to update the Schedule Assessment Guide to keep it current." Until that happens, the December 2015 edition is the document.

GAO developed it over five years — work was conducted from November 2010 to November 2015 — with a committee drawn from government, private industry and academia, and a public exposure draft released in May 2012 that took comment for two years.

Reproduction terms

Quoted verbatim from the guide's front matter:

This is a work of the U.S. government and is not subject to copyright protection in the United States. The published product may be reproduced and distributed in its entirety without further permission from GAO. However, because this work may contain copyrighted images or other material, permission from the copyright holder may be necessary if you wish to reproduce this material separately.

So the text may be quoted at length, and this page does. The second sentence is the reason this page cites GAO's tables by number only and reproduces no figure or table image from the guide: a table or figure may carry material GAO did not itself originate, and separate reproduction of such material is exactly what the notice reserves. Where a table is discussed below, its content is restated in prose and the reader is pointed at the page.

The ten best practices

GAO's names for them, as the guide gives them in its Concepts section:

1. Capturing all activities
2. Sequencing all activities
3. Assigning resources to all activities
4. Establishing the duration of all activities
5. Verifying that the schedule can be traced horizontally and vertically
6. Confirming that the critical path is valid
7. Ensuring reasonable total float
8. Conducting a schedule risk analysis
9. Updating the schedule using actual progress and logic
10. Maintaining a baseline schedule

And GAO's own framing of that list, which is routinely dropped when it is reprinted elsewhere:

The ten best practices represent the key concepts of a reliable schedule. These best practices are in no particular order; they are not intended as a series of steps for developing the schedule.

The numbering is a reference scheme, not a sequence and not a ranking. A few of the individual definitions repay quoting, because they are more specific than the headline names suggest.

On sequencing (practice 2): "activities must be logically sequenced and linked--that is, listed in the order in which they are to be carried out and joined with logic. In particular, a predecessor activity must start or finish before its successor. Date constraints and lags should be minimized and justified." Note minimized and justified rather than prohibited — a difference from the DCMA metrics that GAO itself flags, and one this page returns to below.

On total float (practice 7): "the amount of time a predecessor activity can slip before the delay affects the program's estimated finish date… As a general rule, activities along the critical path have the least total float. Unreasonably high total float on an activity or path indicates that schedule logic might be missing or invalid." GAO names the diagnosis and declines to name the number.

On the critical path (practice 6): "the path of longest duration through the sequence of activities", whose validity matters because "Establishing a valid critical path is necessary for examining the effects of any activity's slipping along this path." GAO takes the longest-path definition. Not every authority does, which is the subject of the standards crosswalk.

On duration (practice 4): "the same rationale, historical data, and assumptions used for cost estimating should be used. Durations should be reasonably short and meaningful and should allow for discrete progress measurement."

The four characteristics

At page 148 the guide gathers the ten practices into four characteristics, in GAO's own words.

Comprehensive. "A comprehensive schedule includes all activities for both the government and its contractors necessary to accomplish a program's objectives as defined in the program's WBS. The schedule includes the labor, materials, travel, facilities, equipment, and the like needed to do the work and depicts when those resources are needed and when they will be available. It realistically reflects how long each activity will take and allows for discrete progress measurement."

Well-constructed. "A schedule is well-constructed if all its activities are logically sequenced with the most straightforward logic possible. Unusual or complicated logic techniques are used judiciously and justified in the schedule documentation. The schedule's critical path represents a true model of the activities that drive the program's earliest completion date" — and the sentence closes with a requirement that total float depict the schedule's flexibility faithfully.

Credible. "A schedule is credible if it is horizontally traceable--that is, it reflects the order of events necessary to achieve aggregated products or outcomes. It is also vertically traceable: activities in varying levels of the schedule map to one another and key dates presented to management in periodic briefings are in sync with the schedule. Data about risks are used to predict a level of confidence in meeting the program's completion date. Necessary schedule contingency and high-priority risks are identified by conducting a robust schedule risk analysis."

Controlled. "Finally, a schedule is controlled if trained schedulers update it regularly using actual progress and logic--based on information provided by activity owners--to realistically forecast dates for program activities. Updates to the schedule are accompanied by a schedule narrative that describes salient changes to the network. The current schedule is compared against a designated baseline schedule to measure, monitor, and report the program's progress."

The mapping

Table 7, at page 149, sets out which practices belong to which characteristic. Restated as a table here; the original is the authority.

Two features of that mapping are worth noticing. Resource loading sits under comprehensive, not under credible — GAO treats it as part of describing the work, not as evidence of realism. And schedule risk analysis sits under credible alongside traceability, which is GAO saying that a schedule with no statement of confidence in its own finish date is not yet believable.

No thresholds, by design

Appendix VI of the guide, at page 183, gives standard quantitative measures for each best practice — and prefaces them with this:

No "pass-or-fail" thresholds or tripwires are associated with the measures. Measures are evaluated in context with qualitative program information and any documented justification. Moreover, severity of the errors or anomalies takes precedence over quantity because any error can potentially affect the reliability of the entire schedule network.

That last clause is the substantive claim, and it is a claim about method: one error in the wrong place can matter more than fifty in unimportant ones, so a percentage cannot be read as a grade. Appendix II of the guide carries the other half of the instrument — the questions an auditor asks about policies, procedures and documentation, which no file parser can answer.

Why this is a different kind of instrument from the DCMA metrics

The two are frequently run together and reported side by side, which obscures that they answer different questions.

GAO makes the comparison itself, in appendix VII, and its own summary is that it found "few substantive differences between best practices detailed in the Schedule Assessment Guide and the DCMA 14PA and other DCMA documentation." It then names the differences it did find. "DCMA assessments allow unlimited use of soft date constraints, while the Schedule Assessment Guide recommends minimizing and justifying their use." DCMA "procedures do not describe guidelines for ensuring that SRAs are conducted properly even if one is required by contract." And DCMA "guidelines do not recommend the use of a schedule basis document or a schedule narrative."

Appendix VII also explains why the difference exists rather than treating it as a defect: "A GAO and a DCMA schedule assessment have inherently different purposes. Notably, DCMA's review focuses on contractor adherence to ANSI standards and contractual data deliverables." Where a contract does not require resource loading, DCMA does not check it; where schedule risk analysis is outside the EVMS guidelines, DCMA does not ask for it. GAO records that in some respects DCMA "measures go beyond best practices described in the Schedule Assessment Guide", on cost and schedule integration and earned value technique.

And, for the reader who arrived here from a software report with a 14-point score on it, the sentence from that same appendix that this site treats as governing: "However, DCMA's 14PA thresholds are not compliance triggers. Rather, they are used as a starting point toward an objective analysis of the schedule."

Reading it

The guide is long, and it is not meant to be read start to finish. Practical entry points:

• Concepts, pages 3 to 4, for the ten practices in one place.
• The best-practice chapters, one per practice, each ending in a list of what the auditor should be able to see.
• Appendix II, for the program questions — the qualitative half.
• Appendix VI, for the quantitative measures, and its refusal of thresholds.
• Appendix VII, for how GAO positions itself against DCMA, NAVAIR, NASA and the other published regimes.

What a file-reading tool can and cannot contribute to any of this is set out in what the result can support, and the divergences between this guide and the delay-analysis documents are in the standards crosswalk.

Related: The DCMA 14-point metrics · Standards crosswalk · How the engine computes a schedule · Glossary

Source: web/pages/gao-schedule-assessment.md. Source commit date: 2026-09-11.