Value-driven maintenance (VDM) is a maintenance management methodology. History VDM was developed by Mark Haarman and Guy Delahay. Both former chairmen of the Dutch Maintenance Association (NVDO) and authors of a book entitled Value Driven Maintenance, New Faith in Maintenance published by Mainnovation in 2004. Value drivers in maintenance In financial literature; value (net present value) is defined as, "Value = the sum of all free future cash flows, discounted to today." A cash flow is the difference between income and expenditure. It is not the difference between turnover and costs, because this is easy to manipulate through accounting. There are companies that use highly creative lease, depreciation and reservation techniques to keep book profits artificially high or low; this does not always contribute to shareholder value. Recent stock market scandals are a painful but revealing illustration of what sometimes happens as a result of this. The second part of the definition concerns the knowledge that the value of a cash flow is time-related, given the term "present value". Future cash flows must be corrected or discounted to today. Managing by value necessitates maximizing future cash flows. Managing by value obliges companies constantly to search for new free cash flows. It's no longer enough for a company to go on doing what it is already doing. Today, it's all about creating value. Now that we know what value is, we can translate the concept into maintenance. Within VDM, there are four axes along which maintenance can contribute to value creation within a company. The axes are also called the four value drivers (see fig 1.). Asset utilization The first value driver, asset utilization seeks to increase the technical availability of a technical equipment. With higher technical availability, it is possible to produce and sell more products with the same invested capital, generating more income while the fixed costs remain the same. In other words, the free cash flows increase, which automatically means value creation. Maintenance can increase technical availability by preventing unwanted breakdowns, scheduling plant maintenance in a smarter way and performing repairs and inspections faster. A point to note is that higher technical availability produces value not only in growth markets. In markets where demand is stable or declining, greater availability can also create value. By making a plant more efficient, the number of shifts can be reduced or it may even be possible to close down sister plants.