Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Search in posts
Search in pages

Go Home

System Dynamics Blog


Practitioner Profiles: Peter Lacey, Whole Systems Partnership

Practitioner Profiles: Peter Lacey, Whole Systems Partnership

by | Mar 4, 2021 | Co-Author : Saras Chung

Welcome to Practitioner Profiles, a series of up-close blog-length interviews with experienced System Dynamics practitioners.  We have a standard set of 10 questions and let practitioners take the responses in any direction they choose.  They tell us about who they are, how they got involved with the field, how they work with clients, and in what new directions they may be heading.  A new profile will be posted every few weeks during 2021. 

For any questions or comments, please contact the editors of these interviews, Dr. Jack Homer ( and Dr. Saras Chung ( 

For today’s spotlight, we talked with Peter Lacey at Whole Systems Partnership.



Peter Lacey, Founding Partner of the Whole Systems Partnership

What does Whole Systems Partnership do?

We work in the health and care sector in the UK, predominantly advising on strategic demand and capacity challenges.

What is distinctive about your approach?

We pride ourselves on integrating SD within a strategic learning cycle and seeking to bring insight alongside other techniques and approaches.  We’re certainly not a one-horse show.  We develop insight for clients in complex strategic challenges, with SD playing a strong supporting role.

What is your role in the organization?

I am Director and owner of WSP, which has a team of eight core employees and a similar number of associates.  I lead some projects directly and oversee others, undertaking model building as well as engagement with clients.  We have four members of the team, including myself, who are competent in SD modelling, but all the rest understand and engage with the contribution that SD makes.

How did you originally get interested in SD, and when was that?

1992.  I was pulled into a project due to the illness of a colleague and received training from Eric Wolstenholme as part of the deal!

What accomplishments are you proud of?

We get positive feedback from clients, particularly clinicians or senior leaders, where the pressure to conform to linear or reductionist thinking is strong.  We win little battles there that signal real changes in mindsets.  Also, we have developed models and approaches that have gone on to influence significant national agendas including whole system workforce challenges and priorities such as the current COVID crisis – not always easy but well worth the effort.  

What challenges have your experienced with the SD work?

We often experience a cultural or philosophical resistance to seeing the world as connected, people preferring to look for answers in siloed ways of thinking.  A command-and-control mentality, or an overreliance on “modelling the data”, can leave senior leaders unable to think broadly or develop insights that are beneficial and have practical value.

What kinds of SD project work would you like to be doing over the next five years?

We’re doing more modelling of population health and how that relates to service demand and capacity, but we’d also like to explore further how health and wellbeing is a function of a wider set of factors.  We’re also doing some conceptual hard work to understand how personal and institutional relationships within local communities may lead to greater resilience and fewer health inequalities.  These are exciting areas where SD insights may be able to correct past mistakes that have been made.

Are there any changes you would like to make in how you approach SD project work?

I’d like to see a greater emphasis on visualisation and how models can best support learning.  Also, more integration of SD with other analytical and modelling approaches.  Systems thinking and SD modelling can provide baseline skills for a wide range of modelling approaches and should not be positioned merely as an add-on or simple alternative.  The ability of SD to generate insights quickly makes it ideal in entry-level training and development.  I’d also like to see much more training for the people who use the outputs from SD models within client organizations.  It is not enough that they get some technical training, but they also need to know how to interpret and reformulate their bosses’ questions to make a model useful—and avoid being “fed to the lions”.   

Have questions/comments? Reach out to Peter Lacey or leave a note below!

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events



The Midlands Decision Support Network in association with The Strategy Unit are hosting INSIGHT 2022 our annual festival of learning and sharing events for the NHS, local government and other partners across health and care. This year’s festival is from Monday...

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

Jack Homer
Jack Homer

Homer Consulting; System Dynamics Society VP Professional Practice
Dr. Jack Homer is a management consultant and expert in System Dynamics (SD) simulation modeling. His models assist organizations looking for a formal yet flexible approach to strategic planning and policy design.


Saras Chung

Saras Chung

Dr. Saras Chung leads SKIP, a facilitation group that fosters equitable education in the U.S.. She also teaches social policy design at Washington University in St. Louis.

Leave a Reply