Value investing has changed over the course of time. Graham and Dodd originally called for a very cautious approach to investing. The goals were to pick stocks using defensive concepts, making sure one only purchased shares that trade below their book value. Using this method helps ensure that future shifts in the market will be safely dealt with.
Throughout the second half of the 20th century, the value of intangible assets became hard to quantify. Patents, branded products and software changed the dynamics of accounting and investing. This was amplified by the continuing evolution of technology, which made judging the exact book value of securities that much more difficult. The new method by which the book value was determined became finding the cash flow values of an asset in the future and discounting it to the present.
Investors have various tools to aid in this endevor including free online value investing software. Investors looking for help with value investing can turn to value stock investing newsletters and value investing funds.