What do clients look for in their agency? In my experience, they value two attributes above all others: integrity and knowledge. Integrity earns respect. David Ogilvy liked to quote one of his clients: “In the end, clients are grateful to advertising agents who tell them the truth.” So learning from what didn’t work is just as important as learning from winners. If we are brave about admitting to our mistakes, we will more readily receive credit when we do well. Integrity helps get us to the client table, but usefulness keeps us there. Knowledge is what makes us useful. We may occasionally fall by chance into an effective solution, but what separates people at the top of their profession from the rest is that they know more. This book is the latest Ogilvy & Mather publication intended to increase our knowledge and, with it, our usefulness to clients. In it, Tim Broadbent deals brilliantly and definitively with one of the most central questions in marketing: How can we measure and increase the effectiveness of our campaigns? This book builds on a core O&M strength, namely a keen intellectual curiosity to find out what works. From the early days when David Ogilvy analyzed mail order campaigns looking for success factors, to today’s “liquid and linked” digital world, we have always believed that creativity is enabled by knowledge. David famously said, “Even a blind pig can sometimes find truffles, but it helps to know that they grow in oak forests.” This book tells you where the oak forests are. 4