How to Create a Good Quality P50 Risk-based Baseline Schedule

Developing a schedule needs to be approached with success in mind. Dividing the project or portfolio into smaller manageable pieces called sub-projects is a good principle, a strategy acceptable and recommended in various industries. However, as the number of activities grows in the schedule, completeness, integration, and alignment challenges become the next hurdle. Key dates end up not supporting each other. The probability of one activity finishing on time cancels out the lower likelihood of another activity and of course, vice versa. The aforementioned happens when sub-projects need to be integrated, and the project portfolio fails to form a cohesive whole.

A disjointed schedule prevents the calculation of the correct critical path. Conversely, a project that can develop a high-quality, complete, integrated, and aligned schedule sets itself up for success. Part of the alignment process available is using P50 dates on all activities across the project portfolio. The purpose of synchronizing the probability to P50 is to increase achievability.

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Three of the project controls books authored by Rufran C. Frago.2018

Any project is capable of generating a believable risk-based schedule baseline. Project confidence is higher when the team knows the target schedule is achievable. It is also cheaper and more economical. Quantification assesses the overall schedule risk of a project. The schedule baseline becomes risk-based because risk probability and consequence are measured. I espouse using a P50 Risk-based baseline as the middle-ground. However, other synchronized schedule baselines such as P40, P60, or higher are also possible.

A deterministic baseline schedule having activities with a different, wide, and varying range of certainty causes significant misalignments that are sometimes unseen to the untrained eyes. The story of two friends narrated in the book “How to Create a Good Quality P50 Risk-based Baseline Schedule (Frago, R. 2015)” explains in simple terms what can happen. The person who is less confident about being on time adversely affects the other person’s activity. It will also influence some of their joint activity. The book guides how to generate this useful benchmark using P6 and OPRA.

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Cover arts by 2018

Suppose one activity depends on another resource to be there before doing the next task. In that case, the successor activity has to wait for the person to arrive, however long it takes. There is a big possibility of overall delay despite one hundred percent certainty of one person to deliver on time. This example supports the recommendation of an aligned P50 Risk-based baseline. Knowing that Pedro missed his plane bound from New York to Florida because the taxi driver was late picking him up from his hotel is simple and so easy to appreciate.

Imagine a 5000-activity schedule with half its resource-loaded activities having a calculated probability of less than 5% (<P5). Yet, the last milestone deliverable of the project says P60. The short-sighted conclusion is to expect completion on time by relying on the calculated 60% probability of the final milestone, or is it? When an activity is less than 5% probable, it is impossible to finish it on time. What would any thinking man expect while looking at the other 2500 activities undermining each other? Delay in the activities, and the whole project is inevitable.

Since the project has 2500 unachievable activities influencing the other 2500, the success of the P60 end date becomes questionable and less attractive. For this reason, my little book will address such disconnect.

The solution is to devise a synchronized probability of a middle-ground target or, perhaps another more acceptable target. Upon completing schedule risk quantification, we create an achievable P50 Risk-based baseline schedule. A P50 baseline has every activity date and duration at P50.

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Frago, R., 2015.How to Create a Good P50 Risk-based Baseline Schedule.ISBN 978-0-9947608-1-4 (Canada)

Frago, R., 2015.Risk-based Management in the World of Threats and Opportunities: A Project Controls Perspective

About the Author

Rufran C. Frago is the Founder of PM Solution Pro, a Calgary consultingproduct, and training services firm focusing on project and business management solutions. He is passionate about providing advice, mentorship, education and training through consultation, collaboration, and what he uniquely calls, student-led training.

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  1. Risk-based Management in the World of Threats and Opportunities: A Project Controls Perspective.ISBN 978-0-9947608-0-7.Canada
  2. Plan to Schedule, Schedule to Plan.ISBN 978-0-9947608-2-1.Canada
  3. How to Create a Good Quality P50 Risk-based Baseline Schedule.ISBN 978-0-9947608-1-4.Canada
  4. Schedule Quantitative Risk Analysis (Traditional Method).ISBN 978-0-9947608-3-8.Canada
  5. RISK, What are you? The Risk Manager’s Poem: Children’s Book for all Professionals.ISBN 978-0-9947608-4-5 (Canada)


  1. Grace, The Guardian Angel.ISBN 978-0-9947608-5-2.Canada
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Book Cover arts by