Practical Software Estimation Measurement

Project Metrics Are the Best Defense in the Battle Against Scope Creep

Scope creep is a frequent topic of discussion among project management professionals.  A recent Project Management Institute (PMI)® i Community Post, Fighting the Dreaded Scope Creep, reported some responses PMI members offered as their weapon of choice.  The various suggestions can be summarized by two general practices:

  • Avoid making on-the-spot decisions (uninformed or politically motivated)
  • Communicate the impact of the change to stakeholders and let them decide (analyze the cost, schedule, and risk impact)

Regardless of the specific practice, all of the recommended defenses included some process for change control.

I like words.  When I need to understand a topic, I pull the dictionary off the shelf (or access the online version), and look at the basic definition.  To determine why scope creep is such a formidable enemy, I looked up the word “creep”:  2. to approach slowly, imperceptibly, or stealthily; 4. to sneak up behind someone or without someone's knowledge.  A vast majority of results from a general internet search defined scope creep as “uncontrolled change.” 

It is easy to see why we’ve adopted this term.  However, I like what Dale Emeryii has to say: “If you take the words literally, they say that scope is creeping. Scope is creeping? What on earth does that mean? Bugs creep. In rush hour, traffic creeps. But scope? Scope is an inanimate thing. It can't creep. Not all by itself, it can't. If scope is creeping, it's because someone is creeping it.”  Someone is creeping it due to a lack of change control. The only way to control change is to be aware of the causes and vulnerabilities of the environment, the situation, and the people.  Having awareness requires data.

Let’s compare it to managing body weight. When the bathroom scale says you are 10 pounds heavier than you were this time last year, you may say that the weight crept up on you. Your body changed gradually, unperceivably. There were times when you were convinced that you made a smart food choice, like eating granola and yogurt for breakfast. Surely this is a positive change over skipping breakfast - the most important meal of the day. But since you didn’t check the fat and calories per portion, you were ill equipped to select an appropriate portion size, select lower calorie brands, or choose to eat a lighter meal at lunch. A lack of data contributed to your loss of control. There are many times when I have had the data, that is, I knew the pan-style pizza and beer were loaded with calories. Yet I consumed them anyway, convincing myself that it wouldn’t matter just this once. In this case, the lack of control is due to viewing the data in isolation, separate from the larger picture that includes my other food and exercise choices.

Project metrics are the key to controlling change and winning the fight against scope creep.  For IT projects, data on effort, time, schedule, size (scope), and defects (Five Core Metricsiii) provide ample visibility into the project status.  They allow project managers to effectively communicate to stakeholders the impact of adding features.  The war against scope creep is not restricted to the battle lines of project start and end dates, however.  It encompasses both the activities that come before and ones that occur after the project begins.

SLIM Suite products provide a complete arsenal to win the battle against scope creep by employing metrics in a broad range of tactics at each stage of the lifecycle:

  • SLIM-DataManager: Software Metrics Project Repository to store historical data and calculate productivity.  Knowing organization and team capacity leads to defensible calculations of the effort and time required to take on additional work.  Record plan vs. actual time, effort, and cost, as well as plan vs. actual size and requirements. Planned versus actual size is important because final size might be larger even if no new features are added if size was originally underestimated (and that information can be used to tune future size estimates).  Recording planned vs. actual requirements shows actual scope creep (features or requirements that are added along the way).
  • SLIM-Estimate: Size, Schedule, Cost & Quality Estimating to quickly and easily analyze multiple scenarios early in the project based upon size and productivity data.  Uncertainty and risk calculations help managers set expectations and layout the project strategy. 
  • SLIM-Control: Variance Analysis & Adaptive Forecasting to track actual scope completion, milestones, effort, cost, and defects against plan.  Multiple metric analyses show true project position.  Forecasting the current trajectory beside alternative scenarios that incorporate additional scope supports effective communication to decision-makers.  The ability to log multiple plans (baseline estimates, revised estimates) shows the delta between each, documenting when and how scope creep occurred and how that impacted the project.
  • SLIM-Metrics: Industry Benchmarking & Process Improvement to observe patterns and identify improvement opportunities using historical data.  Cause and effect of size growth on project performance support both initial estimates and forecasts.  Constructing trends for time/effort/cost overruns vs. size, or size/requirements overruns vs. size, can be used to support multiple estimate scenarios.

Change is inevitable, but scope creep is not.  Successful organizations collect data and have processes built to use it.  These are the best defenses in the battle against scope creep, because impact assessments can be done very quickly, keeping unwanted changes from catching you by surprise.


i PMI is a registered mark of the Project Management Institute, Inc.

ii Emery, Dale H. “Banish the Scope Creep,” April 30, 2003. 

iii Putnam, Lawrence H., Ware Myers. Five Core Metrics, The Intelligence Behind Successful Software Management, (Dorset house Publishing, 2003).

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