Professional Services Intelligence Brief
How to Investigate Rework and Scope Creep
Unplanned work is the most common hidden cost in a services firm. Measure it, find where it comes from and put a simple change process in place before it eats the margin.
Short answer
Scope creep is work added or changed beyond what was agreed without a matching change in fee, time or resources, and rework is work done again because of errors, unclear requirements or late changes. PMI’s 2018 Pulse of the Profession found that 52 percent of projects completed in the prior twelve months experienced scope creep or uncontrolled changes, up from 43 percent five years earlier.[1] Measure hours against budget on every engagement, categorize each variance, and use a written scope and change process; Thomson Reuters calls a missing scope the biggest pricing problem for many firms.[2]
What are rework and scope creep, and how do they differ?
Scope creep is the gradual expansion of work beyond what was agreed, usually through many small requests that each seem reasonable. Rework is repeating work because it was wrong, incomplete or changed after it was done. They overlap: a late client change causes rework, and a vague requirement can produce both. PMI describes the problem as heightened expectations and a quickening delivery pace driving up the risk of scope creep, and reported that 52 percent of projects completed in the last twelve months experienced scope creep or uncontrolled changes, up from 43 percent five years earlier.[1]
Both are costly in a services firm because the product is time. The extra hours may be absorbed under a fixed fee, written down under hourly billing or recorded as non-billable. Each route lowers realization. SPI Research, in a summary by Deltek, defines revenue leakage as the gap between earned and realized revenue, often caused by missed billing, scope creep, write-offs or poor contract controls, and reported average leakage of about 4.5 percent in 2025.[3] Lean’s framework also classifies the repeating of work that adds no value for the customer as waste, called muda.[4]
How do you measure them?
Start with budget versus actual hours for every completed engagement over the last twelve months. Calculate the overrun percentage and list the engagements above 10 percent; SPI finds that overruns above that level harm client satisfaction, margins and future bookings, and that the best firms hold overruns to single digits.[3] Then categorize the variance for each large overrun using a simple code: client-requested change outside scope, client delay or late information, our estimating error, our error requiring correction, unclear requirements, internal handoff problems or other.
| Category | Example | What it points to |
|---|---|---|
| Client change outside scope | Additional reports requested after kickoff | Scope definition and change process |
| Client delay | Data arrives weeks late | Client responsibilities and timelines |
| Estimating error | Task took twice the hours budgeted | Estimating method and history |
| Our error | Deliverable corrected after client review | Quality checks and training |
| Unclear requirements | Draft rewritten after a misunderstanding | Discovery and sign-off at each stage |
Even a few months of coded variances usually reveal a pattern. Most firms find that a small number of clients and a small number of project types account for most of the overrun hours.
What causes scope creep and rework?
The common causes are ambiguity at the start, informal requests, optimistic estimates and weak change control. Thomson Reuters calls the lack of a defined scope of work the biggest problem for many firms when pricing services and managing client relationships, and notes that without a defined scope you may end up doing more work than the client is willing to pay for.[2] It advises scoping the work in advance and making sure the client agrees on what is included and what costs extra, regardless of the pricing structure.[2]
Pressure from clients is real, but the response is often internal: people agree to small favors to preserve the relationship and do not record them. Rework comes from unclear requirements, late reviews, handoffs without complete information and missing quality checks. Deltek adds that long-running projects leave a firm susceptible to scope creep, with clients who either capitalize on it or simply are not aware they are exceeding the original scope, and advises tracking hours worked and tasks completed for each project or client.[5]
How do you control them?
Put four controls in place. First, a written scope for every engagement: deliverables, assumptions, exclusions, client responsibilities, timeline and the change process. Second, a change request routine: anyone who receives a request outside scope records it, estimates the effort and sends a short change order, even when the answer is to do it free as a goodwill gesture, so that the cost is visible. Third, stage gates with client sign-off on requirements before building the next phase to cut rework. Fourth, early warning: review hours against budget when 50 and 80 percent of the budget is consumed and escalate when a project is trending over.
PMI’s guidance in its 2018 article is to establish clear boundaries from the start so key stakeholders understand the plan, and that frequent, effective communication helps prevent scope creep and creates awareness of the harm uncontrolled changes can cause.[1] Hold a short review after each large engagement to update the estimating assumptions and the standard scope language, so each project teaches the next one.
How do you recover the cost?
Use the variance log to price the next engagement properly. If clients routinely request additional reporting, include it in the base scope or sell it as an option. If a client regularly exceeds scope, reprice at renewal or restructure the relationship. Report leakage to the leadership monthly as hours and dollars, for example the value of unbilled out-of-scope work, so it is managed like any other cost. Where relationships remain unprofitable after repricing, see our guide on investigating unprofitable client relationships for the next steps.
Frequently asked questions
What is scope creep?
Work added or changed beyond the agreed scope without a matching change in fee, time or resources. PMI’s 2018 Pulse of the Profession found 52 percent of projects completed in the prior year experienced scope creep or uncontrolled changes.[1]
How do I measure rework?
Track hours by category on each engagement, and log variances against budget with a reason code, such as client change, client delay, estimating error or our error. Review the pattern monthly.
How much do overruns matter?
SPI finds that overruns above 10 percent damage client satisfaction, margins and future bookings, and best-in-class firms keep them to single digits.[3]
Should I charge for every change?
Record every change and estimate its effort. Whether you bill it is a commercial decision, but unrecorded changes make the cost invisible. Thomson Reuters advises agreeing in advance what is included and what costs extra.[2]
What goes in a good scope statement?
Deliverables, assumptions, exclusions, client responsibilities, timeline and the process for changes, agreed with the client before work begins.[2]
What to do next
- Pull budget versus actual hours for the last twelve months of engagements.
- Code the reasons for every overrun above 10 percent.
- Add exclusions, assumptions and a change process to your standard scope.
- Review hours against budget at 50 and 80 percent of each project.
Optional · interactive example
See it in an interactive example.
Firm Economics Dashboard: a service-line dashboard with utilization and realization, a scenario simulator for hours, rate and cost, evidence-linked answers from APIS, and a sample brief, all on synthetic data.
The experience below is built on a synthetic firm, “Demo Advisory Partners,” analyzed by service line. It has no client-level or engagement-level records, so service lines are used to show the method. Nothing in it is real.
- Select Technology Consulting. Compare hours growth with revenue growth.
- In the Scenario tab, lower realized rate by 3%. How much profit leaks?
- Ask APIS which service lines warrant a closer review.
Understand Your Firm’s Economics and Growth Opportunities
Two Pillars helps professional services firms investigate profitability, capacity, pricing and growth using the firm’s own data and a structured assessment process. A good first step is a delivery workflow review that maps how work moves through your firm, measures waiting time and capacity at each step and finds the one constraint that limits output.
Sources
- Project Management Institute (PM Network), Scope Patrol: Scope Creep Is on the Rise as Stakeholder Expectations Increase (Elton, July 2018). Accessed October 2026.
- Thomson Reuters Tax & Accounting, Strategically pricing accounting services. Accessed October 2026.
- Deltek, 5 KPIs from the SPI Professional Services Maturity Benchmark Report Every PSO Must Track for Sustainable Growth (July 15, 2026). Accessed October 2026.
- Lean Enterprise Institute, Muda, Mura, Muri. Accessed October 2026.
- Deltek, 3 Ways to Manage Unprofitable Clients (January 31, 2023). Accessed October 2026.
Sources checked October 2026. This guide is general information for the leaders of professional services firms and is not legal, accounting, tax or financial advice. Figures and rules are cited to the sources below and may have changed since they were accessed, so confirm anything you rely on against the current source. Two Pillars & Co is independent of the organizations cited. See our editorial policy.