Bulletproof Problem Solving

The One Skill that Changes Everything

Charles Conn & Robert McLean

Follow Bulletproof Problem Solving now on YouTube

Co-authors Charles Conn and Robert McLean have completed a series of content pieces for YouTube where both authors discuss their professional experiences, the importance of problem solving, the 7-step Bulletproof Problem Solving process and leading example cases from the book. Follow us on YouTube for more problem solving discussion with the authors.

Click Here to watch the first YouTube piece by Charles Conn 


Sharing ideas on innovation, change, disruption, transformation and the future. Episode 221 has co-author Charles Conn discussing the 7-step systematic approach to how you can become a highly sought-after bulletproof problem solver.

Click Here to listen to the recent podcast with co-author Charles Conn and host Aidan McCullen.

WANT BETTER STRATEGIES? Become a Bulletproof Problem Solver

This episode of Inside the Strategy Room features a discussion between co-author Rob McLean and Chris Bradley, a McKinsey senior partner. The discussion is on how a disciplined and comprehensive approach to problem solving can be applied to almost any kind of problem.

Click Here to listen to the conversation.


Starting with these 5 questions can help you and your team navigate your way through the complexity of planning and decision making that is before us all.

Click Here to read the recent article by co-author Robert McLean


This episode by McKinsey & Company Strategy and Corporate Finance features a conversation between co-author Charles Conn, Hugo Sarrazin, a senior partner in the Silicon Valley office and Simon London, a member of McKinsey Publishing.

Click Here to listen to the podcast.

 Problem Solving in Education  

The 7-step Bulletproof Problem Solving framework is helping students become better problem solvers across the world. 

As taught at Harvard, Oxford, Georgetown, AGSM, Northeastern & the McKinsey Academy

Future of Jobs: Employment, Skills and Workforce Strategy for the Fourth Indus trial Revolution (World Economic Forum, 2016).

Complex problem solving is the core skill for the 21st Century, the only way to keep up with rapid change.  But systematic problem solving is not taught in most universities and graduate schools. The book covers the seven-step approach to creative problem solving developed in leading consulting firms. It employs a highly visual, logic-tree method that can be applied to almost any problem, from strategic business decisions to global social challenges. Conn and McLean, with decades of experience at McKinsey, start-up companies, and environment-focused foundations, provide a toolkit with 30 detailed, real-world examples. 

Rob McLean AM

Rob McLean AM


Rob is a Director Emeritus of McKinsey and Company. He led the Australian and New Zealand McKinsey practice for eight years and served on the firm’s global Director’s Committee. As Dean of the Australian Graduate School of Management (AGSM), Rob saw the growing need for stronger problem-solving capability for business leaders of the future. He is now an investor in mathematics education and data analytics software, alongside his philanthropic interests in conservation and social enterprise. He employs these techniques in his role as a Trustee of The Nature Conservancy in Australia and Asia to address water for wetlands, shellfish restoration and improving human health from urban green spaces. He is a director of the Paul Ramsay Foundation, Australia’s largest philanthropic Foundation. He is a graduate of the University of New England in Australia and the Columbia University Graduate School of Business. He became a member of the Order of Australia in 2010 for his contributions to business, social welfare and the environment.

✉ Contact Rob

Charles Conn

Charles Conn


Charles was most recently CEO of Oxford Sciences Innovation, a £600M venture firm formed in partnership with Oxford to develop the University’s advanced science ideas. Before that he completed a five-year term as CEO of the Rhodes Trust, the organization that delivers the Rhodes Scholarships in Oxford. In this role Charles led a successful transformation effort to refresh the century-old organization’s strategy and operations, including development of a problem solving training program for scholars. He sits or has sat on many company and nonprofit boards, including Patagonia, the Mandela Rhodes Foundation in South Africa, and Arcadia Foundation. Prior to his Oxford roles, Charles was a senior advisor to the Gordon & Betty Moore Foundation, where his conservation projects included the wild salmon ecosystems initiative and the Palmyra atoll research station. Charles was a technology entrepreneur, and as founding CEO of Ticketmaster-Citysearch led the company through its IPO and acquisitions of Match.com, Evite and other companies. He began his career at the Boston Consulting Group and was a Partner of McKinsey & Company. He is a graduate of Harvard and Boston Universities, and Oxford, where he was a Rhodes Scholar.

✉ Contact Charles



“As a former policymaker who argues for moving beyond policy to the broader enterprise of public problem-solving, I welcome this volume! The techniques and insights apply, with various modifications, to problems everywhere: personal, professional, public and private, local, national and global.”

Anne-Marie Slaughter, CEO, New America, Former Director of Policy Planning, U.S. Department of State

“The Bulletproof Problem Solving approach acknowledges the reality many environmentalists face today: this is hard work. Conn and McLean’s guide makes it a little bit easier.”

Mark R. Tercek, CEO of The Nature Conservancy and author of Nature’s Fortune

“Conn and McLean have distilled their matchless experience in attacking challenges of every scale and level of complexity into this virtual war-room of a book, creating an indispensable resource for the 21st century problem-solvers upon whom our future depends.   A must-read for all aspiring change agents!”

Sally Osberg, retired CEO of the Skoll Foundation, co-author of Getting Beyond Better: How Social Entrepreneurship Works

“Navigating ambiguity and solving complex problems creatively is the truth test for humans to complement rather than substitute the artificial intelligence of computers. Without much better approaches to teach those skills, our schools risk preparing second class robots rather than first class humans. Rob McLean and Charles Conn show that this can be done and provide an intuitive roadmap for how to do this, with lots of real world examples that make it fun.”

Andreas Schleicher, Director for the Directorate of Education and Skills, OECD

“Disruption in today’s business environment puts problem solving at the top of every leader’s challenges. But how? This engaging book puts together a McKinsey team’s scientific seven steps approach. From taking a problem apart to rearranging its pieces, to framing it so its solution can be seen, the book presents a must read analysis for executives and social sector leaders. It excites both the reader’s mind and the possibilities for project teams.”

Glenn Hubbard, Dean and Russell L. Carson Professor of Finance and Economics, Columbia Business School

“Great strategic problem solving is an essential tool, one whose value is only going up. Bulletproof provides the secret sauce behind the McKinsey framework to help structure and guide the problem-solving process. I want to hire people who understand this approach.”

Barry Nalebuff, Milton Steinbach Professor, Yale School of Management and cofounder, Honest Tea

“The old paradigm of strategy departments and planning cycles has been overthrown by agile and rapid team-based problem solving, providing  better solutions and better organization alignment to implement.  This book, written by two of the smartest people I know, provides the needed blueprint for how build these world-beating problem solving teams.”

Mehrdad Baghai, Chair Alchemy Growth and author of As One

“The world has never been in more need of extraordinary problem solvers-in business and every other walk of life. Rob McLean and Charles Conn powerfully demonstrate that problem solving is a structured process that can be learned and applied to the benefit of everybody. Their book is such an important contribution to the resolution of our biggest problem solving challenges.”

Nick Lovegrove, Professor of the Practice, Georgetown University and author of The Mosaic Principle

The book has more than 30 case studies. We show two simple ones here to pique your interest in learning more.

Click to expand and view case studies list

Case Study: Should Rob Install Solar Panels on His Roof Now?

A few years ago Rob thought it might be time to install solar panels at their house in the Australian countryside. Rob and his wife Paula wanted to do something to offset their carbon footprint for some time, but were struggling to make a decision with reducing (and now eliminated) subsidies available from the power company, declining costs of installing solar PV, and questions over the future level of feed-in tariffs (the price at which the electricity company buys from you when you generate excess power at home). Was now the right time? He decided to approach it in the way he had learned at McKinsey and started with the hypothesis, “We should install solar PV now.” He hadn’t reached a conclusion by framing it this way, nor was he setting out to confirm it without regard to the facts. He was using the hypothesis to bring forth the arguments to either disprove it or support it.

    Rob felt that the hypothesis would be supported if the following criteria could all be sustained:

    • If the payback on the investment was attractive, something less than 10 years.
    • If the decline in the cost of panels was slowing down such that he should not wait and make the investment later at substantially lower cost. Rob felt that if solar panel costs were going to continue to decline and be significantly cheaper in three years he’d consider waiting.
    • If the reduction in his CO2 footprint was material, by which he meant 10% or more (other than air travel he is required to do and can offset independently).

    Rob knows that constraining the scope of the problem with clear boundaries makes problem solving more accurate and speedy (step 1).

    Step 1: Define the Problem

    This kind of problem sounds quite complex at first, a jumble of unfamiliar terms like feed-in tariffs and avoided carbon. A logic tree helped Rob see the structure of his problem in one picture, and helped him break up the analyses into manageable chunks. He started by laying out the reasons and supporting facts that he would need to resolve the issue. You can also think of it this way—for Rob to answer the question affirmatively what would he have to be convinced of? What are the major reasons for going ahead and installing solar panels?

    Exhibit 1.5 is a first cut of Rob’s logic tree (steps 2 and 4).

    Exhibit 1.5

    The first part he tackled was payback, because if the economics didn’t work, the two other questions didn’t need answering. Payback is pretty straightforward: the cost of the installed solar panels and inverter, divided by the annual electrical cost savings. The denominator in this analysis includes both estimating net savings from the installation from avoided electricity charges because he was using his own power, plus income from supplying electricity to the grid via feed-in tariffs. Most of this analysis can be done by online calculators that solar installers offer, once you know the size of the system, roof orientation, solar electric potential and the efficiency in power generation. Rob simplified the analysis by leaving out battery storage options that add to cost but provide the opportunity to replace peak power charges. With an annual cost savings of around $1,500 and investment costs of just over $6,000, payback was attractive at about four years (step 5).

    The next question was whether he should make the investment now, or wait, hoping for lower solar panel costs later. Rob was aware that the cost of a watt of PV had fallen almost 30% from 2012 to 2016, and almost 90% from the early days of solar PV. He wasn’t sure whether this would continue in the future. With some simple Internet research, Rob learned that declining costs of equipment was still uncertain, but the cost per watt was unlikely to fall by more than 30% for at least the next three years. There is also uncertainty about future feed-in tariffs that have been set to encourage sales of solar PV. This has to be considered against rising retail prices for electricity customers.

    At $1,500 per year, the cost savings lost by waiting would be $4,500 over three years, so the upfront cost of the solar PV installation would have to fall by 75% to make waiting worthwhile. Rob could have used a net present value analysis where the time value of money is considered rather than a simple payback. But in this case the simple method is fine: He felt comfortable that the four-year payback providing an implied rate of return of 25%. It was worth doing now.

    Finally, he wanted to estimate how much of his CO2 footprint he would reduce by going ahead. This depends on two things—one is what fuel source he is displacing (coal or gas in this case) and the second is the kilowatt hours (kWh) he is generating compared to his electricity use, which he knew from the first step. Rob simplified the analysis by looking at the carbon footprint of the average Australian citizen, and found that the avoided carbon from his little solar project could reduce his footprint by more than 20%. Since the payback as an investment is very solid in this case, Rob really could have pruned off this branch of the tree (step 3) and saved some time—but he and Paula had multiple objectives with this investment.

    Whenever you do this kind of analysis it is worth asking what could go wrong, what are the risks around each part of the thinking? In this case there is a chance that the power company would reduce the subsidies for installing solar PV. This can be mitigated by acting quickly. The power company could also reduce the feed-in tariff rate at which it purchased any excess power produced by Rob—and in fact they did that later. But with a four-year payback the exposure is reasonably limited.

    The result of Rob’s analyses is shown in the more complicated tree shown in Exhibit 1.6.

    Assumptions: House type: detached bungalow, Roof orientation: north, Slope: 40°, Suitable roof area: 40m2, Installation size: 5kWh, Shading: none, Numbers for calculations are from 2017, Australia.

    With only a bit of online research, Rob was able to crack a relatively complicated problem. Rob should install solar panels now: The payback is attractive, and likely cost declines to install later are not enough to offset the savings he could earn now. As a bonus, Rob and Paula were able to reduce their carbon footprint by nearly 30% (steps 6 and 7).

    The core of this good result was asking the right questions and disaggregating the problem into straightforward chunks.

    Case Study: Making Pricing Decisions in a Start-up Company

    In the past few years, one of Charles’s friends started a company that makes an accessory for pick-up trucks that has a unique and clever design. The company, which we’ll call Truckgear, sells around 10,000 units a year, a number that is growing quickly. It is at breakeven on a cash basis (cash basis means not taking into account the accounting charge for depreciating assets). Charles invested in the company and helps devise its strategy.

    Start-up companies face big and complex problems early on in the process and, compared to larger companies, they have limited cash resources and team members to address them. Truckgear had to make decisions on whether it should own its own manufacturing plant, which market segments to compete in (there are new and used truck segments and several sales channels to each), whether it should have its own sales force, how much to spend on marketing, and most fundamentally, how fast to grow given limited cash? No wonder start-up teams hardly sleep!

    Recently the company had a big decision to make: Should it raise its prices (step 1)? It had held its initial pricing of around $550 for three years. Materials and manufacturing costs had increased as the product features were improved, crimping its margins and lowering the cash generated per unit. Obviously in young companies cash is even more critical than in established ones, as the sources of external financing are significantly fewer. The dilemma Truckgear faced was this—if the marketplace reacts negatively to the price increase, Truckgear growth would slow and perhaps even drop in unit sales?

    There is no perfect answer to this kind of question, but we employed a particular kind of logic structure to assess it, a profit lever tree (step 2). We wanted to hone in on the key factors around the decision, and this kind of tree is mathematically complete, so we could use it to model different assumptions.

    Exhibit 1.10 is a simple version of this kind of tree.

    Exhibit 1.10

    You can see how the tree makes Truckgear’s problem visual: Pressure on costs pushes down variable margin per unit—can the company increase unit prices without slowing sales growth or even dropping volume?

    Exhibit 1.11 displays the numbers for Truckgear.

    Exhibit 1.11

    If the company could hold its current unit sales, a price increase of 7% would yield a $385,000 improvement in cash profitability, a substantial increase that could help fund additional marketing and sales programs. But you can also see that it would only take a drop in unit sales of 650 to neutralize the benefit of the price increase (step 5). What to do?

    Whether a price increase leads to a loss in total cash profit (or, less seriously, slowing of growth) depends on competitor pricing, customer price sensitivity (which economists call price elasticity), whether the third-party dealer sales channels will absorb some of the price increase by accepting lower margins, as well as marketing and sales efforts. The company initiated a large phone survey of its recent customers and determined that:

    • The largest volume customer segments were not sensitive to a modest cost-based increase.
    • The competitor products were roughly comparable in price and quite different in functional characteristics.
    • Dealers were not willing to reduce their margins to accommodate the price increase.

    The company also evaluated whether it could achieve the same result by reducing its fixed overheads or taking manufacturing in-house. With few costs other than a lean staff and rent, the first was not an option. With limited current cash resources, investing in its own extremely expensive manufacturing presses and assembly also didn’t make sense (step 3). On balance a small price increase to restore unit margins was worth the risk (step 6 and 7).

    This kind of financial tree is particularly useful for solving problems that involve monetary trade-offs of alternative strategies. You can use it to track almost any kind of business problem.