As a former consultant at McKinsey, my personal experience working with the firm and conducting interviews with hopeful applicants gave me a different point of view on this question.
The low quality of material marketed to aspiring consultants is one of the foremost problems that led me to create My Consulting Coach. More than 90% of applicants come across Cosentino's Case in Point. Half of them will use it as the main guide for preparation, and the other half will use other formulaic, framework-based systems. These systematic programs and guides are what you will find on almost every website selling preparatory guides for case interviews.
This frustrated me to no end as an interviewer. Working consultants do not use these algorithmic frameworks for projects to overcome problems as quite often fall apart when up against complex real world cases. Put another way, if a client brought a problem to McKinsey able to be solved by methods available online, or through a book found in the library, clients and businesses alike would solve the problem themselves at a fraction of the cost, instead of $3,000+ per day for a novel solution by an experienced consultant.
Interviewers are well aware of the framework-based systems and all their failings, and it is unlikely they will give you a case simple enough to fit easily into any single framework. More often the interviewers give cases based on their most recent projects, with all the difficulty and complexity of the real world. What they will want to see is an approach those cases in the same way they approached the cases. They want to see you have given much thought to the scenario and offer a proper solution to the problem. What they find egregiously tiresome and a lackluster showcase of ability is the forceful use of arbitrary frameworks on cases. Sometimes you can't fit a square peg in a circular hole, especially if the instruction manual is for a circular peg.
There is a better way
My Consulting Coach has developed a wide range of resources to help you get that MBB offer by thinking like a consultant, instead of memorizing a list fo frameworks.
A) Our case interview method
Our case interview course has been developed by MBB consultants with clear goals in mind - To teach you how to think, act and communicate like a world-class strategy consultant. By going through it you'll become equipped not only to ace the interview process, but also to be a top performer at your firm.
Other methods focus on helping you memorize dozens of frameworks and pre-packed structures. We take a different approach. We believe that distinctive candidates and distinctive consultants don't rely on crutches and that they use their own minds to solve the toughest problems. We're here to help them master the concepts and processes they need to be able to shine. We can support you in:
1) Understanding business fundamentals: Get your mini-MBA with our Marketing, Strategy and Economics, Accounting & Finance modules
2) Learning how to crack a case: Identify the problem, Build a problem driven structure, Lead the analysis and how to provide recommendations.
3) Shaping your approach with our building blocks: Master profitability analysis, competitive dynamics, pricing discussions, among others.
B) Our coaching sessions
help the best candidates to pinpoint their development points and turn
them into strengths. They will give you self-awareness about your
profile and how to best position yourself for that MBB offer. Equally
importantly, they will give you the confidence to know you can succeed
in such a challenging process.
c) Other resources
We offer a broad assortment of resources, with a large portion of free materials and services. There is a free meeting board you can meet and talk with case partners from around the world, a free case bank of more than 35 cases to practice with, and a wide range of helpful articles on how to refine your performance in all aspects of the consulting process. As for the PST, My Consulting Coach has a page to help you here.
It's important to remember that preparation is not only memorization of an easily digested formula. It involves necessary critical thinking, and studying the right things. Most websites will give you the easy path, but this is not always the correct path.
Good luck in your endeavors, and remember -- "By failing prepare, you are preparing to fail." - Benjamin Franklin