3-Points Estimation Technique

3-Points Estimation Technique

The most useful scheduling technique which, in my opinion, has to be used in each project is 3-Points estimation technique. It is simple to use, it improves team productivity and project performance.

As projects complexity level keeps growing, projects become less predictable and project plans are usually built based on expert opinion, rather than accurate historical data. Very complex projects are so unpredictable that companies move from Waterfall to Agile delivery methods, where 100% of activity estimation is based on expert opinions.

Regardless of a delivery method, when team members are forced to provide a single estimation (duration or story point) for each activity, they have to include a “risk factor” as a hidden contingency. This is leading to a number of challenges:

• PM is not aware of activities with a high-risk factor
• PM doesn’t control contingency
• Opportunities to complete activities earlier decreased due to Parkinson’s Law
• Risk to activities delay increased due to Student Syndrome

Parkinsons’s Law

Parkinson’s Law
work always expands to fill the time available for its completion.

Some team members will use allowed durations even if the risk is not actualised.

Student Syndrome

Student Syndrome
An activity owner is likely to delay a start of activity as “hidden contingency” creates an illusion that there is still enough time to complete this activity on time. However, if the risk is materialised there is no sufficient time to complete the activity on time as hidden contingency has already been spent.

3-Point Estimation

3-Point Estimation:

When activity estimation is based on an expert opinion, it’s always preferable to capture three estimations to understand potential variance of durations

a) What is the BEST possible (optimistic) scenario to complete the activity?

b) What is the WORST possible (pessimistic) scenario to complete the activity?

c) What is the MOST LIKELY scenario to complete the activity?

• It doesn’t take much longer to capture 3 numbers instead of 1, but it enables immediate understanding of activities with hidden risks;

• It is important to capture BEST and WORST estimations before the MOST LIKELY estimation. It forces an estimator to think about potential issues before MOST LIKELY duration is provided;

• Activity TARGET duration could be calculated based on 3 estimations. PERT formula could be used as an initial proxy.

• The key project delivery dates could be calculated with two different approaches:

a) based on TARGET durations;
b) based on OPTIMISTIC durations with overall contingency bucket;

• Regardless of a target approach an activity owner has to plan an OPTIMISTIC duration as his own target, but not to be punished if it takes longer to complete the activity.

• It’s always useful to run analysis on the deviations from optimistic and target durations. Usually after 20% of project progress is achieved, as normally there is sufficient data to understand if target dates of outstanding activities need to be adjusted.

• Activity owners always appreciate 3 points estimation technique, as it takes pressure from them.

• The method is a great alternative to story points technique in Agile projects.

• 3 estimations are also a base for more advanced scheduling methods: Monte Carlo Risk Analysis, 3 Scenarios Method, Probability of Success.

Target Durations

A target activity duration could be calculated with or without a weighted factor:

a) Triangular technique recommends using average of three estimations:
Target = (O + ML + P) / 3

b) PERT technique recommends using a weighted approach:
Target = (O + 4 * ML + P) / 6

PERT = Program Evaluation and Review Technique

I prefer PERT, as it gives a more accurate prediction. Optimistic and Pessimistic scenarios may occur but usually, it doesn’t happen as often as Most Likely scenario and PERT address it.

Example: Travel to office

In an ideal scenario with all green lights and no traffic, I can reach my office in 25 minutes. In very bad traffic it’s never been longer than 60 minutes. Typically, it takes 35 minutes.

O = 25 mins
P = 60 mins
ML = 35 mins

Target travel time (average): (25+ 60 + 35) /3 = 40 mins
Target travel time (PERT): (25+ 60 + 4* 35) /6 = 37.5 mins


PERT formula is a good proxy if there is no actual data available. However, after ACTUAL completion dates become available for analysis, the formula could be adjusted to address specifics of the project, organisation or even experience of an estimator. Some estimators are too optimistic, others are too conservative.

For example:
T = (2 * O + 5 * ML + P) / 8

In some cases, I had to revise outstanding target dates for the whole project, in some for end of current phase and in some just for one or two estimators.

Scheduling Tools

Huge advantage if this technique is that TARGET estimations could be easily calculated in Excel. However, it is very convenient to use a scheduling tool instead. It saves time, support “What if analysis” and could be used for more advanced risk evaluation methods.

MS Project versions 2013 support PERT analysis. Target durations could be calculated based on PERT formula or the formula could be adjusted.

MS Project version 2016+ doesn’t support PERT (!!!). However, Project 2016 PERT Add-in is available.


Primavera doesn’t support PERT analysis. Target calculation has to be completed in Excel and then entered as planned durations.
However, external tool – Primavera Risk Analysis (previously known as PERTMASTER®) has integration with Primavera and could be used for PERT or Monte Carlo analyses.

Spider Project has built-in 3 points estimations and supports advanced risk methods: Monte Carlo Risk Analysis, 3 Scenarios Method & Probability of Success method.

For more mature projects Spider Project allows to link Optimistic, Pessimistic and Most Probably versions of a schedule together. The versions could vary not just with different activity durations but also with different activities and different logic between activities to address risk contingency and risk management plans.

Spider Project has a free fully-functional version limited by 40 activities. This version could be used to develop a fragment of a schedule with 3 points estimation. The fragment then could be exported to Primavera or MS Project.

Spider Demo version:

A lot of 3rd party tools available for PERT and Monte Carlo analysis.
Acumen Risk is quite popular enchantment. Especially for scheduling tools, like Primavera, which don’t have built in risk management.


I will write a separate topic on how to enhance Agile delivery with 3 points estimation technique. As a simple alternative ask to provide 3 durations and calculate Story Points based on these estimations. It gives much better visibility of a risk factor and improves team performance.


• When activity estimation is based on an expert opinion, it’s always preferable to capture three estimations instead of one.

• Project may continue to use only Most Likely estimations but knowledge of Optimistic and Pessimistic scenarios should improve project performance as “Parkinson’s Law” and “Student Syndrome” issue are going to be mitigated.

• Target durations are more accurate comparing to Most Likely option as it takes risk and opportunities into account. Target durations could be calculated based on 3 estimations. PERT analysis could be used as a good proxy to start from.

• More advanced risk methods could be applied to use 3-points estimation data.

Alex Lyaschenko

PMO | Portfolio Planning & Delivery | PMP | P3O Practitioner | AgilePM Practitioner | Six Sigma

Supporting tools for planning and scheduling

Supporting tools for planning and scheduling

Show me you scheduling toolkit and I can tell you who you are!

Successful planning and delivery of complex programs and portfolios are not possible without application of best scheduling practices and advanced methods. Application of these methods and practices is difficult without appropriate tools to support them.

Traditional Program delivery tools, Microsoft Project and Primavera, enable only some practices and methods. If no supporting tools are used, program and portfolio delivery is going to be limited by capabilities of these tools and could not be optimised to full extent.

Application of additional scheduling tools differentiates mature scheduling consultants from junior project managers and schedulers. Some Project Managers and schedulers are too much tool focused. They have good (sometimes quite deep) knowledge of Microsoft Project or Primavera and believe that their tool is the best scheduling tool in the world and no other tools are required. However, if these specialists expand their experience and learn more from scheduling masterclasses, they will realise that applying supporting scheduling tools is critical for successful program delivery.

Good scheduling consultants have their own set of “tools” they bring with them to mature program and portfolio scheduling for their clients. In this article I’d like to share some of my “toolkit” items.

For over 20 years I’ve used many different tools to support my clients with program planning and delivery and/or portfolio optimisation. I still continue to discover new tools and also develop my tools further.

I would group scheduling tools in three main categories:

  • Basic scheduling tools
  • Advance scheduling tools
  • Supporting tools

Some tools could be used in both areas – as a scheduling tool and/or supporting tool, depending on a particular client case.

Basic scheduling tools:

Some of the tools below are not scheduling tools but they have capability to manage project plan to some extent:

  • Excel;
  • Project for the web;
  • CA Clarity;
  • Planner;
  • Jira;
  • Trello
  • SAP

Advanced scheduling tools:

  • Primavera (P6);
  • Microsoft Project and Project Online (MSP);
  • Spider Project (SP);

Supporting Tools

Supporting tools could be grouped by area of application:

  • Risk Management
  • Quality Assurance
  • Resource Management
  • Data Analysis
  • Reporting

In Australia majority of my clients use MSP or P6 and the most of supporting tools have been used to complement these two systems.

 These approaches I used were dependant on customer’s needs:

 Develop a customised tool in Excel

Typically, it requires some macros development. I used this approach many times almost for all clients.  

 Custom development

Tools in Excel could give quick wins and increase maturity level very quickly, but usually these are used as a tactical solution, rather than a strategic approach.

Large organisations have an opportunity to access in-house developers and/or engage professional services to develop additional features in a scheduling tool.

P6, Project Online and Clarity do have this capability, but it is important to understand that this approach has some serious limitation. Certain core functions could not be enhanced even for a fortune. Also, this may increase complexity of systems and cost of upgrades. So it is really critical to perform proper impact analysis before custom development commences.

 System Add-ons

MSP has a big advantage over P6 in this space, as it allows to develop macros and installation of 3rd party add-ons (an add-on is an embedded feature which does not require import / export).

MSP add-ons are usually not so expensive and sometimes are even available for free. However, be careful as some of them may impact system performance.

In general, MSP macros are very helpful and could optimise scheduling processes, integration with another system or simply make schedule more user friendly.

 3rd party tools

I used 3rd party tools when there was no opportunity to enhance core functionality of MSP and P6. It is critical that the 3rd party tools have high quality import/export function and support core MSP and P6 features. For example, Clarity does not support some critical MSP features. This is causing differences in dates after a MSP schedule exported to Clarity.

Some tools are so critical for mature planning & scheduling that we (as Salute Enterprises) have purchased them to support our clients project management needs. These tools have a good proven global record of enabling successful delivery.

In case when tools are specific and are only applicable/preferred by a certain customer, that customer would pay for the tool themselves.

 WBS Schedule Pro

Usually mature Program planning & schedule development starts with WBS (work breakdown structure) development. WBS Schedule Pro tool is very supportive in this space. It helps a lot with developing the structures quickly and is powerful during stakeholders’ reviews and scope verification sessions. An alternative approach would be to use Visio linked to a scheduling tool.

 Spider project (SP)

While SP is a powerful advanced scheduling tool (when I only can, I use it as an alternative to MSP and P6), there are many clients who have a policy to use a certain corporate scheduling system. In that case I use SP as an additional tool. Usually I use it when I need to optimise a schedule developed in P6 and MSP. SP has much better capability for data analysis, resource optimisation and schedule risk analysis. As per my knowledge SP has the best algorithms in the world that enable resource critical path calculation, supports Monte Carlo and 3-points risk analysis methods.

Also, as SP keeps all versions of a schedule together, I think it’s absolutely unbeatable as a tool for the trend analysis (which I am a big fan of).

Primavera Risk Analysis

Some of my clients with P6 scheduling standard have already had a chance to appreciate Primavera Risk Analysis. We used Primavera Risk Analysis to estimate program contingency based on the Monte Carlo analysis.

It works perfectly. The only challenge I have with this tool is around resource constrained schedule analysis. This tool doesn’t support critical chain and the contingency is build based on the critical path method (not resource critical path). It would be so much better and easier if this tool was built in P6 directly.

In case when resources are unlimited or manual resource optimisation is possible (for small projects and a few critical resources it’s acceptable) this tool gives good result.

Deltek Acumen Fuse

For simple schedule quality analysis, I use my own set of filters in MSP and P6 and applying them after each schedule update. A tool in Excel is an option when I need to complete analysis of a number of schedulers and share results with the client.

For more detailed analysis my preferred option is Acumen Fuse.

The tool has over 100th metrics to analyse quality and performance of schedules and particularly is useful for vendor schedule analysis. It allows custom configuration and could be configured in alignment with clients scheduling standards.

Unfortunately, I have seen some misuse of this tool in some of the organisations when a “Master scheduler” who actually didn’t quite understand the purpose of this tool, was forcing PMs and Schedulers to complete DCMA-14 points full assessment with a reference that “it is a recognised standard” around the globe.

Reporting systems

Both MSP and P6 have built-in reporting system which I used from time to time, mostly for my own analysis. However, when I need to develop user friendly reports, it’s always done outside of these systems.

I have seen an Integrated Master Schedule as long as 100 page print. Of course, it was “too complicated and detailed” and no one used it.

For quick wins I often use Excel. It’s flexible and allows to incorporate customer’s feedback fairly quickly. For more mature analysis such as (e.g.  Linear Diagrams, S-Curves reports) it’s  much more easier for me to use Spider Project reporting engine, rather than tailoring this all in Excel. Especially when these advanced reports are in big demand for my clients.

MS Visio I use mainly for roadmaps and schedule management processes. It is possible to link Visio objects to Excel or even MSP data and update roadmaps much quicker. This approach is more useful when there is a good project management maturity level.


This tool is quite handy for high level program timeline reports.

BI Reporting Tools 

An alternative option and as a more sustainable, long-term solutions is to use BI tools: Tableau or Power BI. Each of these tools has its own advantages (and unfortunately constraints) but often it is a matter of a corporate choice. Power BI is a traditional choice for technology projects, as it could be linked directly to Project Online. When I can, I use both systems (with Data Warehouse and Alteryx) utilising advantages of each system.

Often PMOs have access to BI system developers who could support with development of advanced dashboards, interactive IMS reports (and a version which could be saved as PDF) and many other type of reports. But it requires good scheduling standards to be implemented, as a format of P6 and MSP data extract (or backend connectivity) has to be stable for this automation to work properly.

Do you have your own toolkit, which you prefer to use to complement P6 and MSP and to increase the level of maturity in planning & scheduling? Please share.

Alex Lyaschenko

PMO | Portfolio Planning & Delivery | PMP | P3O Practitioner | AgilePM Practitioner | Six Sigma