Decision Tree Analysis in Project Management 

A Practical APM PMQ Example That Helps You Choose the Best Option with Confidence

Decision tree analysis is one of the most powerful yet underused decision-making techniques in project management. If you are preparing for the APM PMQ exam, or working as a project professional making real investment decisions, this technique helps you compare options objectively using probability, cost, and expected value.

In this article, I will walk you through a complete decision tree example step by step using the slide shown below. By the end, you will understand exactly how to calculate Expected Monetary Value, how to identify the best option, and how to confidently answer exam questions.

NOTE: I have repeatedly shown the main Decision Tree graphic several times in this article – this is to help reduce scrolling and improve context when reading about detailed calculations.

This is not theory. This is practical, exam-ready decision tree analysis.

Decision Tree Example Used in This Article

The slide below shows a full decision tree scenario comparing two strategic options:

• Develop a new product
• Consolidate the existing offering

Each option contains further decisions, probabilities, costs, and benefits.

What Is Decision Tree Analysis in Project Management?

Decision tree analysis is a structured decision-making technique used to evaluate uncertain outcomes. Project managers use it to compare alternative strategies by calculating expected value.

This technique is commonly used in:

• Business case development
• Investment decisions
• Risk response planning
• Product development strategy
• Procurement decisions
• Portfolio prioritisation

The APM PMQ syllabus expects you to understand how to construct and interpret decision trees and calculate Expected Monetary Value.

The key principle is simple:

• You build the decision tree linkages from left to right
• You calculate the values from right to left

This single rule helps avoid most exam mistakes.

Step 1: The Initial Strategic Decision

At the far left of the diagram, we begin with the first decision node. The organisation must choose between two strategic directions:

• Develop a New Product
• Consolidate the Existing Offering

This is a classic project portfolio decision. One option focuses on innovation and growth. The other focuses on optimisation and efficiency. Each strategy leads to further decisions.

Step 2: Analysing the New Product Option

Under the New Product route, there are two possible approaches:

Detailed Development with a cost of £125K
Rapid Development with a cost of £40K

Immediately, you can see the trade-off. Detailed development costs more but may produce higher returns. Rapid development costs less but may limit benefits. This is typical in real-world project decisions.

Let us analyse Rapid Development first.

Step 3: Rapid Development Expected Monetary Value

Rapid development has three possible outcomes:

• Best case with probability 0.1 and benefit £500K
• Average case with probability 0.2 and benefit £25K
• Poor case with probability 0.7 and benefit £1K

Now we calculate the Expected Monetary Value by multiplying each benefit by its probability:

• 0.1 × £500K = £50K
• 0.2 × £25K = £5K
• 0.7 × £1K = £700

Now add these values together:

£50K + £5K + £700 = £55.7K This gives us the expected value before costs.

Now subtract the development cost of £40K:

£55.7K − £40K = £15.7K So the net expected value for Rapid Development is £15.7K.

We now complete the first branch.

Step 4: Detailed Development Expected Monetary Value

Now we analyse Detailed Development. This option introduces another layer of uncertainty, which is very common in large projects. There are three possible outcomes:

• Best case probability 0.4 benefit £500K
• Average case probability 0.4 benefit £25K
• Poor case probability 0.2 benefit £1K

Calculate expected values:

• 0.4 × £500K = £200K
• 0.4 × £25K = £10K
• 0.2 × £1K = £200

Add the values:

£200K + £10K + £200 = £210.2K

Now subtract the development cost of £125K:

£210.2K − £125K = £85.2K This is the net expected value.

Step 5: Comparing New Product Options

We now compare the two development approaches:

Rapid Development = £15.7K
Detailed Development = £85.2K

Detailed Development clearly provides the higher expected value. This becomes the preferred option within the New Product branch, which is why £85.2K is highlighted on the diagram as the most valuable option.

Step 6: Analysing the Consolidation Strategy

Now we return to the original decision and analyse the second strategic option, Consolidate.

This branch contains two possible approaches:

Increase Functionality with cost £15K
Cosmetic Improvements with cost £NIL

This is another typical project decision. One option delivers functional value. The other improves presentation with minimal investment. Let us start with Cosmetic Improvements.

Step 7: Cosmetic Improvement Expected Value

There are two possible outcomes:

Best case probability 0.6 benefit £10K
Poor case probability 0.4 benefit £1K

Calculate Expected Monetary Value:

0.6 × £10K = £6K
0.4 × £1K = £400

Add the results:

£6K + £400 = £6.4K

There is no cost, so the final value remains £6.4K. This completes the Cosmetic branch.

Step 8: Increase Functionality Expected Value

Now we analyse Increase Functionality.

This option has three possible outcomes:

• Best case probability 0.3 benefit £200K
• Average case probability 0.4 benefit £10K
• Poor case probability 0.3 benefit £3K

Calculate Expected Monetary Value:

• 0.3 × £200K = £60K
• 0.4 × £10K = £4K
• 0.3 × £3K = £900

Add the values:

£60K + £4K + £900 = £64.9K

Now subtract the implementation cost:

£64.9K − £15K = £49.9K. So, the net expected value is £49.9K.

Step 9: Comparing Consolidation Options

Now compare the two consolidation strategies:

Increase Functionality = £49.9K
Cosmetic Improvements = £6.4K

Increase Functionality clearly provides greater value, so this becomes the preferred option within the Consolidate branch.

Step 10: Final Decision Comparison

We now return to the original decision.

Compare the best options from each branch:

New Product Detailed Development = £85.2K
Consolidation Increase Functionality = £49.9K

Detailed Development under New Product provides the highest expected value.

Therefore, the recommended option is to Develop a New Product using Detailed Development with an expected value of £85.2K. This is the final decision highlighted in the diagram.

Why Decision Tree Analysis Is So Powerful

Decision trees remove opinion and replace it with structured logic. Instead of arguing about which option feels better, you calculate which option provides the highest expected value.

This improves:

• Business case quality
• Investment decisions
• Stakeholder confidence
• Governance decisions
• Portfolio prioritisation

It also helps project managers justify recommendations with evidence. Senior stakeholders respond strongly to structured, quantified decision-making.

Real World Application for Project Managers

Decision tree analysis is not just for exams. Project managers use it regularly when:

• Selecting vendors
• Evaluating delivery strategies
• Choosing technology platforms
• Prioritising features
• Assessing risk responses
• Planning product launches

If you want to move into senior project roles, this type of structured decision making becomes increasingly important.

Learn More with My APM PMQ Masterclass

If you found this example helpful, my APM PMQ Masterclass goes much deeper. I walk you through:

• Decision tree analysis
• Expected monetary value
• Risk analysis techniques
• Business case development
• Real exam style scenarios

Everything is delivered in structured, easy-to-follow masterclass videos.

You can join here:

You will get access to the full range of project management masterclasses designed to help you pass exams faster and improve your real-world project skills.

Final Takeaway

Decision tree analysis gives project managers a structured, logical, and defensible way to make complex decisions, and in this example, we:

• Built the decision tree
• Calculated expected values
• Compared options
• Identified the best strategy

The final recommendation was clear. Detailed Development under the New Product strategy produced the highest expected value of £85.2K. And that is exactly how decision tree analysis should work.